Welcome back to the Scarman Labs Podcast, the show where we break down fermentation science for brewers at every level. I'm going to be your host today, Richard Priest, CEO of Scarman Labs. Today, we're going to be joined by other co-founder of Scarman Labs, Nate Ferguson. I'm going to be talking about a blog post that he just put out on crashing beer. And we're going to get into all the benefits of slow crashing versus fast crashing and what you need to know. I'm going to be a little bit of a physics lesson today just to give you some warning. This episode is brought to you by Scarman Labs, delivering precision and yeast and passion and craft. From clean loggers to the juiciest of IPAs, our mission is to help you understand and control the variables that matter most. Subscribe wherever you listen so you never miss an episode. So, if you brew beer commercially, you've probably had this debate with your co-workers, which is better, slow crash or fast crash. Do I really need to step crash or can I just drop that thing down to zero and move on with my week? And how is crashing a beer like a game of Tetris? We've got Nate here to help us demystify beer clarification and settling. So, welcome Nate. Hello, glad to be here. Okay, let's get into it. So, just for reference, we're going to be covering a lot of the topics that are in this blog post that Nate put out. The reason we decided we wanted to put this on the podcast is because we noticed that when we shared this blog post and put it on Instagram and all the social media's. It did well. It did well. There was clearly a lot of people sharing this and talking about it. So, clearly we struck a chord here. Yeah. There seems to be some interest in this topic, slow versus fast crashing of beer. So, what we often hear as a standard practice for breweries is to crash cold and crash fast. But why is that possibly the wrong approach? So, in order to explain why that, you know, just rushing straight down to night 2C or zero degrees Celsius. I'm sorry, I can't recall the Fahrenheit on those 32F. You really have to understand what we're trying to remove. In order to explain this, we have to really look at the two different types of class of molecules that we're trying to remove. And those are. We can kind of call them organics or non organics and non organics, which for us is yeast cells or the organics and non organics. These would be things like proteins and polyphenols. Now, they do share some similar protocols or physics associated with them. However, we really got to think about removing the two types of molecules as separate entities because they do respond to different stimuli. They respond to different things that can accelerate their sedimentation. Okay. Maybe before we get into the details of this, could you just quickly explain why do brewers cool their beer when fermentation is done in the first place? Right. So, there's a handful of reasons as to why we want to cool our beer. The first one is kind of a practical reason to CO2. We want to try and capture some of the CO2. This is more of a macro thing. We have to capture some of the CO2 inside of the beer. This helps prevent oxidation later points. If we have a little bit of built up CO2 pressure, like a 1.96 or so grams per liter or so of CO2 inside, we're going to have a little bit of positive pressure inside of it, which will just make the processing of the beer smoother and less error prone. The bigger reason though is clarity. And this is why we see it being done now. If we were to go back in history and look like English style beers being brewed a couple hundred years ago, they weren't cold-crashed. These are beers that pretty much will stayed into the cold as they would be. You'd be seller temperatures like 12, C or so give or take. And for the large portion of ale manufacturing, we weren't bringing the beers down to zero. It was just whatever temperature the seller got to. Now, some of the terms that we use are kind of the notion of why do we go to zero or two degrees Celsius or just as cold as possible. A lot of the stems from what I can tell from Czech and German style brewing. So what they would do is, if you go to the old school methods of logger manufacturing, they'd make their work, they'd let it ferment cool, but again, just seller temperature, whatever that cooled, cold seller would be. And they would do this in October and November time period. And then it would get colder. So the seller just got or the beer just got as cold as the environment was. So if you look at the Czech area, they're more hype in the mountains. They would have 90 days or so of cooling. If you were to look at the Germans, especially the Bavaria, or it's a bit warmer, so lower in altitude, they had a shorter winter. So you'd see shorter, longer in periods for it. I think that process, people noticed, was improving the clarity of their beers. They're just a visible clarity of it. If you want to go down the rabbit hole, you can look at the history of glassware and its cost and opaque versus non-opaque glassware and see when people actually started caring about this. But yeah, it also has some kind of flavor or mouth feel textural benefits to it. If we go this cold, we will remove certain elements from the beer that can be harsh or rougher or jagged. Yeah, and like you talked about, there's basically two things we're trying to get out of solution when we cold crash. And that is the yeast cells as well as anything that's inorganic that isn't a yeast cell. So I think you said this right at the start, but your proteins and polyphenols and all these things that can form hazes. Absolutely. Yeah. So in order to kind of explain this, I think it really makes the most sense to look at the two individually. We'll start with yeast and then move into protein and polyphenols after. Sounds good. I'm always interested in talking about yeast as we all know. How does crash speed affect yeast flocculation or settling? So in order to explain this, we have to look at what causes the yeast cells to flock at the begin with. And that is the expression of this type of gene that we see in yeast cells called the flow genes. FLO, pro, there are a series of molecules that bind the yeast cells together. Now, the yeast cells require time in order to respond to make this protein. So what can happen, especially if we've, you know, the beer hit just hit FG, the yeast cells might be doing some flavor cleanup or they just finish doing like the acid or a sea of aldehyde cleanup. They then need to pivot and start making these flow genes so that they settle out. If we start crashing too quickly, the yeast cells won't have enough time to produce these enzymes decreasing the ability for them to flocculate out. That's the biggest issues for it. With a practical benefit of step crashing is that because we're going down, say, one degree C or two degrees, even a couple of, even a four degree Celsius a day, we're giving the yeast cells more time to respond, produce more of these flocculation proteins, enhancing their ability to flocculate out. In a practical standpoint, we kind of see some people accidentally or unintentionally do this with a lot of NEPA production, where they're doing a step crash mainly to help stave off, you know, secondary fermentations or things like that. A practical benefit of this is that we are putting the yeast cells kind of in that ideal temperature range to maximize their flocculation gene expression, which is my hypothesis that haven't tested this, but this is my guess is that is why brewers have a lot of success harvesting yeast cells off a partial crash, like a step down. We're like a saw, you hear people call it a soft crash. Soft crash, that's the word I was talking before. That's the word I was talking about. So that's what I was talking about, I was talking about the increase to do the dry hopping or the yeast cropping or whatever, right? Exactly, that's what I was looking for. So that soft crashing temperature will optimize the yeast cells. It's enough of a signal that tells the yeast cells, yes, I need to start producing these proteins, but it's not so cold that they can't, they just go completely dormant, but it's also colder than fermentation temperatures, they're no longer looking for sugars. Don't push the analogy too hard. Yeah, but I guess your point is that the yeast needs to be able to make those flocculation, those flocculent proteins. Absolutely. And if it's too cold, it can't do that. And there's sort of a time window here where they have to run out of sugar first, basically, before they express those proteins. Exactly. Ideally, there'd be more research on this. There isn't a ton, but that generally is how we believe it functions. And in practice, that's how it functions. And it's known that it's what's called glucose repressed. So for example, when there's still glucose around, then the expression of those flocculent genes is repressed, so it doesn't happen. Yeah. So glucose is kind of the main trigger there. Absolutely. So that's the, one other bit I'd want to put when it comes to just the yeast portion of this before I move over to the protein polyphenol on organics. Is when we, if we have an inconsistent flocculation, so let's say we have some of the yeast cells that are super highly flocculent, other ones, we did something to them, they're stressed, they're pissed off, something's unhappy with them or sick. We're going to start seeing these differences and densities within the yeast cone. So we may have certain portions of healthy yeast cells that flocculated very tightly together, and other ones that are more of a loose kind of more fluffy for like a better word. This becomes, this causes a problem when we start looking at harvesting our yeast cells, because the liquid on top is going to want to follow the path of loose resistance. So wherever we have these kind of fluffier or looser sections of the yeast cake, we are going to see those areas get drawn off first. This is a prime, prime way to induce tunneling in your, in your, when trying to crop. For those just to, to say it tunneling is when we are, they're still yeast inside the cone of the fermenter, especially for a CCV at closed conical vessel. But we're, and we're trying to pull that yeast off, but we're just getting beer. The beer is tunneling through the yeast cake down to where we're trying to harvest, which causes losses, causes frustration, cuss words are uttered. It's not a good time. Yeah, and I do find that that can happen when you crash aggressively, because yeah, that first settling yeast can just get really stuck to the sides, like on a conical tank.
So I imagine that slowing down the process might help that to settle a little bit more evenly. Absolutely. Perhaps. Or even even more in kind of cleaner, tighter layers. Like, yeah. This is strictly hypothetical, a thought experiment, but it would make sense to me that we'd have all of the healthier yeast cells flocculate more tightly at the bottom. And then above that, we'd see, you know, the unhealthy cells would flocculate at a slower rate, giving us a more loose mesh, but we'd still have a significant decrease in tunnel in chance. Yeah. Before we move on, actually, that's something I wanted to ask you about because it's something that we've, that I've talked about with some clients and some who have success with this. But I wanted to get your thoughts on the practice of actually rousing the tank or the ferment before initiating crashing to encourage the yeast cells to collide with each other because I know a few of our clients do that and that's helped them to improve how they get that yeast crop out, especially with the soft crash. Like, there's a few folks out there that I've been talking to lately that are having great success with repitching by, you know, basically rousing the tank with CO2 once it's passed FG and once it's passed, you know, forced to ask for all that. And then immediately after initiating a soft crash and they're able to get a really good crop of yeast quite quickly. So what I'd about to say is completely on, there's no research paper, there's nothing like that. This is, this is strictly just me, you kind of walking mentally through it. I wouldn't be surprised if, so the yeast cells that are the most healthy are going to be the ones that flocculate out first. Well, not exactly first. They're, we'll see some yeast strains that are under-attannuative. Yeast strains that have lost maybe the ability to consume maltotriose or they have less affinity for myltotriose. Those will flocculate out first. But after that, we'll then have more of our healthy ideal yeast cells. I would not be surprised that if we, by pushing CO2 inside the tank and resuspending those, they're almost kind of act like a finding agent, almost where they can go up. They have these flocculation genes already there and they're able to grab onto all the other yeast cells that are inside the tank and then pull them down with them. The other, that's kind of like a biology angle on it. From a physics standpoint, I could see this working where we are kind of how we just mentioned about tunneling. If we push a bunch of gas through, we are going to disrupt any of those areas that were less dense. We could actually, essentially, agitane are shaking out all of the less dense areas, create a more uniform cake. That's those ideas. I don't know if anyone has done the research on that. I think, and in particular, this seems to be effective with chain forming yeast, like foggy yeast. I mean, I don't know if you've ever opened a tank of a beer fermented with a London 3-type yeast, but often it'll be at final gravity done for mening and like, there's still yeast floating on top. And so breaking that up by rousing, yeah, it's a top cropping English strain. Breaking that up with rousing can also help to make sure that it settles out nicely. Yeah, it makes total sense for what people are seeing. I don't want to say it's non-standard. I don't want to discourage people from doing it, but if it's working for you, excellent, don't stop doing it. But I don't know of anyone who's been on that a paper or anything like that on this, but it's in theory works. Yeah. I mean, the way that I always try to visualize flocculation is like you just have a bunch of tennis balls and velcro balls, and the more you can throw more of them together in the same space, the more likely they are to stick together and make that heavy, heavy flock that settles out. Yeah, the only thing I'd want to push on that a little bit from the analogy is that it does start to cause, and this is only really an extreme case, but there is a thing called the Zeta potential. It's actually in one of the videos we talked about. I think it's for clarity in the longer series, where it has to do with charge balances. So let's say we have too many positives or too many negative charges, because the same charge repels similar charges, those charges can kind of create like this, like bouncing a elasticity element to that actually prevents things from flocculating out. So if we had too much of a charge, the yeast cells couldn't, in fact, repel each other assuming the flocculation protein isn't over-express, which is generally positive. Right. Yeah. I mean, I think my analogy still works. Oh, yeah, still works. Yeah. The two tennis balls that don't have enough velcro on them, they're going to bounce off each other. Yes, absolutely. Yeah, absolutely. You know, if the tennis balls are yeast cells and the velcro is our flocculent protein. Yes. Absolutely. All right. So the other, on the topic of charged particles, the other thing that we're settling out when we crash, cold crash, a beer is the non-organics. That's the protein, polyphenols, things like that. Why do those behave differently from yeast? So they're mainly because they're dead. That's the main reason. They're not a lot. So these molecules are strictly based on physics. We're looking at solubility. We're looking at stokes law. We're looking at how do we get these molecules out? So in order to explain the approach here or how it's different, the first guy talking about stokes. Is that where you're like, you're really stoked about your double-decoction coaster? Is that what that means? No, it's named after. I want to say the guy is George or George Stoke. It's a fellow's name. He's been, he's long dead. Long, long, long time. But yeah, so Stokes law is what we, I think we should start for this. And Stokes law states simplified that the more denser and larger particles settle faster. And of those two variables, the most important one is the larger. So if you want to look it up, you can Google online Stokes law. You'll notice that the radius value on it is squared. This means that if say we double the size of the particle, we're going to see a 4x increase in the speed of its sedimentation. So this is the theory, so the principle that a lot of finding agents work on. We're looking to have all the difference. Say we had a finding agent, I even Irish Moss or Izing Glass, if you want to go old school. It's going to make the molecules much larger, therefore radically increased, sorry, make them much larger by binding to them or binding multiple of them together to massively increase the radius, dramatically causing the settling speed to go down. So that's the first law. We have to look at Stokes law. More dense is better. Larger is also better. Those are the two things that have to cause these molecules to come out. We then have to look at their binding. So proteins and polyphenols are the two main types of inorganic molecules that we are looking for. This is the other half when we start looking at fast versus slow. If we co-crash these beers quickly, the interactions that we have between the proteins and polyphenols are going to happen crudely. They're not going to happen efficiently. And this is going to cause a less dense and arguably still large, but not as large as it could be, particle. This is where the tetris analogy comes in. I think if we're playing tetris at the very beginning, it's slower. We can figure out where we're going to put the next piece with a lot more confidence. It's easier. If it's near the end of the game, we've been playing for a couple of minutes. We're going faster. We have to figure out where the piece goes. Find and put it over there because I don't know where to put it. That's going to be gone. Oh, we got it. Yeah, there's going to be gaps. It's going to be potentially fluffier. Exactly. Exactly. So the molecule, like we're going to have more pockets inside of our cake or inside of our protein polyphenol mix. In extreme cases, if we do this too quickly, it actually causes the binding of the proteins and polyphenols to curse so loosely that it almost represents a gel. But these micro gels really are really tricky and difficult to remove. And then not just remove from a settling standpoint, they're also terrible to filter out. They, because they're larger, they'll bind filters up and blind them, blinding being the, or the entire filter surface, because it's completely covered, therefore, the flow rate, the pressure differential sky rocket, the flow rate goes down. We can't do much with it. Can destroy filters, whether there be a DE filter or a cartridge filter, a string filter, well, it doesn't matter. So we really want to try to avoid those. Now, the other flip side for this just has to do a temperature. And this is where I think some people, they kind of, they kind of miss the forest for the trees to a certain degree, or they don't understand the context for, like, the whole picture. So if you go to the macro guys, the macro guys, they get their beer down to like zero to, some, some people even get negative, negative two, negative three degrees Celsius. Yeah, that's what I've always been told is, you know, minus one is the best for dropping out chases. At for chill haze, exactly. And that this is true. So as we make the liquid colder, the, the ability for the liquid decreases, if we look at the nets to get, not to get tuned to the weeds for this, but the overall net hydrogen bonding capacity of the liquid decreases as temperature goes down. I regret you inform you we are already in the weeds. So what this means is that, we'll bring it a little bit, hydrogen bonding capacity is the ability for water to absorb things in the liquid. And it's typically when we're trying to absorb a molecule, say, like, say, like, as proteins are polyphenols, it's not just one molecule of water binding to it. It's many. So when we decrease the temperature of the water, the ability for the water to dissolve things decreases significantly. Now we all probably kind of intuitively know this. If you've ever tried to make a simple syrup or dissolve something in liquid, you've noticed that if it's warmer, it happens faster. So we're really trying to use this concept to cause everything to come at a solution as much as possible. And when we do this, the molecules become more likely to bind to each other, become larger, become more dense and crash-yped. That's the concept behind it. If we want to really get the beards down as cold as we possibly can, like negative two, we're doing this even more so. Now negative two works, maybe we might be thinking, like, how can we freeze the beer? Because of the alcohol content, especially from a high-gravity brewing standpoint, we can get the negative two and the alcohol means that we're not going to be freezing the beer. So that's an edge case.
that is an edge case. You can pretty safely bring like a five or six percent logger down to zero, but I wouldn't want to go much past that. - Yeah, really. - That would be another caution to be honest, just on the practical side with fast crashing. Like if you have a fairly large tank, where the diameter's pretty big, and your cooling jackets are just on the outside, like I've seen cases where hard crashing down to minus one minus two, whatever, or even above, you create different temperature gradients in the tank. Like I've seen ice formed in, you know, - Oh yeah. - Oh, yeah. - Oh, yeah. - Oh, yeah. - Oh, yeah. - By doing it. So I guess that's one practical caution, potentially against the fast crashing. - Yeah, we're already in the weeds. I don't feel bad talking about this. But one thing that's also really important to think about here is the temperature of your glycol. So I'll use here as an example. We hold our glycol around negative 10 to negative 15 degrees Celsius to pay on the time of the year. Some places go much colder, much, much colder. So the glycol flowing into your jacket of your tank isn't the temperature you want the beer to be. It is a much colder temperature. If you increase or decrease the flow rate, if you have, you know, solenoids that are a gradual open close versus hard on offs. If you don't have control valves or flow rates to balance these things out, you can, you know, have micro areas where you are freezing things, which is a little outside the scope of what we, what I mentioned here, but it's important. - Most of our listeners are professional brewers with the glycol system that barely works. (laughing) Mostly works. - I'm not gonna mention manufacturers. (laughing) So this idea of going down super cold is good. It is a good idea, but it is a huge element on this. That's really important. And this is one of the things that the macro guys do, that the craft beer guys don't realize that they do. And that is that they pre-filter or kind of, just get rid of the yeast cells, centrifuge at least, the beer before it hits those negative degrees Celsius ranges. And this is incredibly important because if we go and say it is even zero and we have yeast cells present, the yeast cells will freeze and they can die. And when they die, they produce a lot of autolytic or negative flavor tones in our beer. So if you wanna go to these really, really cold temperatures, it's very important that you get those molecules out. It's very important to get those molecules out. Like we need to be dropping the yeast cells. You know, if you go to gnarzes or things like that, you're talking daily or every other day. Choose your own adventure little bond that, you need to make sure if you're gonna go that cold, you cannot have yeast cells active or even present in that fermenter. - Okay, so let's talk about that. So in terms of yeast removal, just sort of from a clarity standpoint, but also just from a yeast management standpoint, what's the best practice if we're looking at crashing? - So I'm a big fan of the Thomas Sol quote that there are no, what is it? There are no solutions, there are only trade-offs. So to say what the best is, I feel a little uneasy about that. There's pros and cons to each. So if we, ideally, we would be harvesting yeast cells immediately after FG has been reached. That's the ideal. - Yeah, that's one of the kind of the healthiest. - Exactly, they just finished having a meal. They just did a bunch of exercise. They're energy reserves and they're highest. We don't need them to starve for a week before we can use them. Let's get them out of the kitchen. Let's get them out of the hard, sweaty, difficult environment. That is the ideal is, you know, let's harvest them right after. Now we're not gonna get all of them. How are the cells out? How are the cells that we do get out are going to be ideally the healthiest. Because we haven't gone super cold or anything yet, we're our chance of having stratifications and density or our chance of tunneling is typically less if we harvest them right at FG. That's the ideal. Now, typically if you do it then, you're gonna get enough yeast cells out of the tank to repitch at least one more tank. And this is the downside. You're not gonna get the standard for the macro guys is about a 4xing of yeast biomass. So if we had 10 trillion cells and 10 hex at the end of that ferment, we ideally would have 40 trillion cells inside that batch. We're not gonna get that. - Yeah, we're gonna get two doubling. So that's always the kind of the standard. - Exactly. So we're not gonna get all those cells out. But we are gonna get a lot of the really good ones out. We can then go through whatever our crashing protocol is and start removing the yeast cells every day, every other day, every third day. It in a matter that makes sense for you. But if you don't need the yeast cells, this is, and you're just dumping them, this is a lot easier. If you do need the yeast cells, maybe do like two or three days slower crash on it and let the cells accumulate, harvest them out. That's one option for it. If you, you know, if you wanna add the additional complexity to it every single day and you might get half a pitch out of it, which, you know, not a good use of resources being your time. But it works. If you're a large brewery, it's a good idea. Yeah, what I would not do is I would not want the yeast, I would not want to be reusing the yeast cells that have been in a fermenter for two weeks. (laughs) - Right, yeah. - That's the worst case. - Yeah, that's not gonna treat the yeast very well. - No. - It's sitting under pressure and, you know, without food for a long time. It's surrounded by alcohol. It's pissed off. It's not good. - Okay, so, I mean, as a general practice, we could say, grab the yeast you need for your repitch early on in the question process. - Early on. - Absolutely. - Like actually your soft crash. - Yeah, you do not need to wait until you've reached your final temperature in order to harvest. That's actually a really important part to hammer home. 'Cause I've had, I've had lots of students who have this, were like, yeah, I can't harvest until we've hit, you know, we've hit temperatures like that's not correct at all. You should harvest now. - No. - I mean, we do crop yeast at like two here, but that's also, there's like other practical considerations - Absolutely. - For what we're doing. - We are not making beer. - Exactly. (laughing) I will say, you know, okay, speaking from our own experience, you absolutely can, you know, soft crash, 15-ish, and harvest yeast, you're still gonna get the majority of the flocculation. - Yep. - That way. Obviously, you don't wanna keep it at that temperature. It will, you know, it will lose vitality and viability faster if it's not chilled. - Absolutely. - You know, getting the yeast out into a brink, and then if you do have to store it, putting it in a cold room is great. Just another question for you. So just based on all the things we've learned, if just fast crashing has these trade-offs, what would you recommend, how slow should we actually go? - So your, the question here really is, what's the, you know, the return on investment, the, you know, labor to impact ratio on here? I'm gonna talk for alieast, and then do a separate bit for longer yeast, 'cause those, I think you do have to handle them differently. For alieast, a crash somewhere between like 14 and 16 degrees cells, this probably makes a ton of sense, just to help enhance the flocculation gene expression, and then to go down. Now, the slower we go, the more tight those yeast cells and the protein polyphenol matrix will be. So, you know, it depends on what you're trying to go for. If you want this beer to be completely clear, and you don't have a filter any way to do that mechanically, going two degrees Celsius per day probably makes a lot of sense. Now, if you are just looking at the bulk of it out, you're okay with a little bit of haze, do like a 16 degrees Celsius drop, then maybe go to 10, kind of break it up into a few different staggered steps. If you really wanna dial it in, do one degree Celsius a day. That's what the classic Vansha-Fon Narza's method is, is one to two degrees Celsius per day. - Yeah, that temperature program of like almost dropping as it's finishing fermentation. - Yeah, so one other bit on this, and this is, I haven't had a chance to prove this, but this is just from conversation, sorry, I can find the text for it 'cause it's in German. This is from conversation with people, is that this concept wasn't necessarily, it was almost found, not designed. If you were to put, say, a tank full of 20 degrees Celsius beer in a room, that is at zero degrees Celsius. These are some breweries where they have single-walled vessels that can hold pressure inside of a cold room, and that's how they cold crash their beer. In that situation, the beer is going to be slowly. - It takes a while, yeah. - It takes a while. So we're kinda naturally going like one or two degrees Celsius down per maybe not day, but half day. Just based on the physics of the thing, 'cause we're not using glycol, because the cooling medium is air. That's where they believe this method kind of, what I've heard, that's where I've heard people suggest this method came from, was that we can now replicate with glycol, what we've known to work based on our cave experience. That's just an important-- - It all comes back to the caves. - It all comes back to caves as long. - We're not sure. - We've heard of Plato's cave now. - I was just gonna say, let's talk about-- - Let's not talk about-- - No, it's Narcissus cave. - We're not talking about Plato's cave. (laughing) - I think it's a little too dark. (laughing) So yeah, the question of like how well do we, how cold do we crash for ails, like make sure you hit a 16, I'd say, and then just kinda stagger it from there. One thing we didn't have in mention is either cold chalk proteins or cold chalk stress that can happen. If the yeast cells are in the chilled too quickly, they will create certain molecules that can arguably, again, poorly studied from my understanding. Decrease the protein con or decrease the body of the beer, like the mouth feel characteristic of it. I don't know much about it, but I've just been passing in a little bit so that where if he stressed the yeast cells out due to this sudden temperature shock that they could secret proteases or something like that, that decrease the body. I don't think there's any studies on this. I could be wrong on this, but-- - Yeah, I'm not familiar with anything on that topic. - Yeah. - I was talking with a guy at CBC, CBC about this,
It was fun. I thought it was fun. So that's those are ails. When it comes to loggers, we gotta talk about one or two different kind of other elements on it. And that is that the flocculation genes inside of loggers yeast are kind of broken. They don't indifferent. Yeah, indifferent. So they don't, like the ideal temperature, like you know 14 to 16 degrees Celsius for ail, for ails is in many cases above the fermentation temperature for loggers. Just based on selection criteria, these genes have been mutated, turned off, damaged. Because otherwise the yeast cells wouldn't ferment. They just flocculate out and do nothing. So there is a bit more of a physics angle we have to take for logger yeast. We do have to kind of do what we do with protein and polyphenols, just colder, slower. We want to make sure that network and that meshing, kind of the tetris thing of the yeast cells is tighter. They do have some flocculation genes. Don't get me wrong, they do have some, but their expression is messy. And their function is poorer than aile yeast. Yeah, I mean the loggers tend to be a little bit below average compared to aile yeast with, I mean some aile yeast who are just like insanely flocculent. But even generally, we tend to sort of see them in that, like 40th percentile. Yeah. And just one other thing that this is anecdotal and some of the we've kind of encountered when it comes to logger yeast flocculation is that magnesium seems to play a decent role, like a larger role than it would be in aile yeast. So like if you, one of the things we, I've recommended in the past is if you are seeing issues with logger yeast flocculation and you are doing the other things that are right, adding some additional magnesium, whatever the source you use, tends to benefit, tends to help. Yep, those critical cofactors, magnesium and zinc, those are so critical for gene expression as well. Yeah, die-failing cations, man. [laughs] This is some of my favorite metals. [laughs] So yeah, the kind of, if I were to give a whole like summary on this, the slower we go, the more tightly any sort of molecule inside a solution is going to compact and settle out. And that's a good thing. That's what Stokes law says. The more dense the particle is, the faster it's going to settle. The slower we go, the more likely we are to have all these molecules bind each other in large chunks, or flocks. So Stokes law again, double the radius, 4x is the velocity going down to the speed of settling. So the slower we go, we're going to see more compact, more even distribution of, it's called, of whatever the yeast cells or the proteins or the polyphenols, whatever it may be. Particles. The particles, exactly. Now, you know, we don't want to have, we don't want to draw this out to be 20 days. We don't want to go into 20 degrees Celsius. We'd want to degrees Celsius per day. That is economically non-viable. So you're always having to work with the limitations of your brewery. The way I would suggest people really try to look at this or try this is if you're having beers that are persistently hazy or like you're spending a day filtering this thing, or just that they won't clear, if whatever the reason, try this. You're going to have, you are likely to have some, at least see some improvement with what you're looking for. If you're having issues collecting enough yeast cells, try a step crash. This is a tried and true method to try and get more yeast cells out, get more haze to settle out of the beer. And it's more in line with what the yeast cells evolutionary wise have experienced as well. It's like you're kind of primed for this. Yeah, that would say also if you're using findings as a final touch to remove haze, the more you can do naturally through a process like this, that's going to give you an easier time later on with your cold findings as well, using something like a silica salt or-- Bio fine. Yeah. Yeah. And they're typically more impactful, too. Those things are-- doubling the amount you add is very, very infrequently going to be twice as effective. So if we have a lower amount of haze that needs to be removed to begin with, we're typically going to see what we would normally add to be more impactful. Absolutely. Well, I think that's a pretty good summary there. We have it. The physics of why rushing your cold crash might be holding your beer clarity and yeast health back. Sometimes the most efficient path is the slow one. Slow and steady wins the race in this case. Sometimes you've got to go slow to go fast. If you're testing step crashing in your brewery, let us know how it goes. Nate, any final words for the listeners? If you want to learn more, go to our YouTube channel. We have lots of different content. We've just been wrapping up the logger series that we've been doing for a while. We have videos on high-gravity brewing, yeast-cropping, clarity, settling, all sorts of things. You want to improve the quality of your loggers? Go check it out. Lots of logger knowledge over there. Also, visit asgarminlabs.com for our full library of resources, knowledge-based, and fermentation guides, including our guide to yeast management and repitching, which also covers some of the topics that Nate discussed today. Make sure to send your questions to
[email protected]. We always use these to come up with topics for the podcast. And if you haven't already, please subscribe to the Asgarminlabs podcast wherever you listen, tell your friends. We're here to help you with all your technical knowledge. So that's it for this episode. Thanks for having me. Nate, cheers. My pleasure, cheers.
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