20 replies to this topic

[Big Nake]

I think that the most mysterious part of homebrewing is the yeast. There is a lot of talk about its proper care, health, harvesting, its impact on making delicious beer, how much to use, how to nourish it, how to aerate it and exactly... how much is a BUTTLOAD of yeast? I'm bringing this up because I reuse yeast a lot. When I make a starter for a beer, I plan to make 2 or 3 beers with that same colony of yeast. Almost all of my beers run from about 4% to close to maybe 5.5% so I don't have situations where I'm pushing tolerance limits. Because my beers are lower, I often make small starters (650ml of water, ½ cup DME) and pitch the entire thing when it's active. The first batches that I make with a new starter ALWAYS come out good. Then I harvest that yeast at the end of primary 1 and I have a good 700ml of thick slurry... sometimes more, sometimes less. Some brewers will tell you to pitch that whole thing because you need a lot of yeast. But how do you know what else is in there (break material, hops schputz, dead yeast cells)? I often make subsequent batches that turn out well, but I also get second or third batches that just don't come out was nicely as the first one and I always wonder why. Jamil says that you always want the yeast to reproduce some amount because the reproduction actually produces flavors that beer drinkers find pleasant. If you pitch too much yeast, you may not get those flavors and the beer's profile may be flat. So how do you guys harvest and reuse your yeast? Do you wash it? How much thick slurry do you guys repitch? If you harvest 600-700ml of slurry, do you pitch it all or divide it between 2 batches? I feel like this is one area where I am partially blind. Cheers.

[cavman]

I think that the most mysterious part of homebrewing is the yeast. There is a lot of talk about its proper care, health, harvesting, its impact on making delicious beer, how much to use, how to nourish it, how to aerate it and exactly... how much is a BUTTLOAD of yeast? I'm bringing this up because I reuse yeast a lot. When I make a starter for a beer, I plan to make 2 or 3 beers with that same colony of yeast. Almost all of my beers run from about 4% to close to maybe 5.5% so I don't have situations where I'm pushing tolerance limits. Because my beers are lower, I often make small starters (650ml of water, ½ cup DME) and pitch the entire thing when it's active. The first batches that I make with a new starter ALWAYS come out good. Then I harvest that yeast at the end of primary 1 and I have a good 700ml of thick slurry... sometimes more, sometimes less. Some brewers will tell you to pitch that whole thing because you need a lot of yeast. But how do you know what else is in there (break material, hops schputz, dead yeast cells)? I often make subsequent batches that turn out well, but I also get second or third batches that just don't come out was nicely as the first one and I always wonder why. Jamil says that you always want the yeast to reproduce some amount because the reproduction actually produces flavors that beer drinkers find pleasant. If you pitch too much yeast, you may not get those flavors and the beer's profile may be flat. So how do you guys harvest and reuse your yeast? Do you wash it? How much thick slurry do you guys repitch? If you harvest 600-700ml of slurry, do you pitch it all or divide it between 2 batches? I feel like this is one area where I am partially blind. Cheers.

I usually use around 300ml of harvested yeast per 5 gallon. On imperials like the Hoppy red I recently brewed(1.092 OG) I try to time it to rack onto the cake of a small beer, where the small beer is basically a drinkable starter. I've been considering using chlorine dioxide to wash my yeast as my local brewpub recommended it. https://www.brewings.../yeast_care.htm You can get it at NB now https://www.northern...lets-20-ct.html

[JimInNJ]

My attempts to reuse yeast usually result in a fast start, vigorous fermentation, under attenuation and over carbonation. I wonder if reusing yeast may call for greater amounts of O2.- Jim

[Big Nake]

I failed to mention that I sometimes just use the contents of a swollen Activator and end up with great beer (again, probably a ~5% beer). If you use the yeast calculator on Jamil's site, it seems to suggest that the amount of yeast you need is lower than what many homebrewers suggest. I also never understood it when brewers say they're making a 1L, 2L, 3L starter... I can't envision how much actual YEAST they're talking about. When I make my starters with 650ml of water and ½ cup DME, I end up with a thin layer of yeast on the bottom of my starter flask and that small amount of yeast ends up making great beer. This is what makes me think that OVERPITCHING can be an issue. If that small amount of yeast makes such good beer, why would I need 700ml of slurry the next time around? Or am I missing something?

[cavman]

I failed to mention that I sometimes just use the contents of a swollen Activator and end up with great beer (again, probably a ~5% beer). If you use the yeast calculator on Jamil's site, it seems to suggest that the amount of yeast you need is lower than what many homebrewers suggest. I also never understood it when brewers say they're making a 1L, 2L, 3L starter... I can't envision how much actual YEAST they're talking about. When I make my starters with 650ml of water and ½ cup DME, I end up with a thin layer of yeast on the bottom of my starter flask and that small amount of yeast ends up making great beer. This is what makes me think that OVERPITCHING can be an issue. If that small amount of yeast makes such good beer, why would I need 700ml of slurry the next time around? Or am I missing something?

Try yeast washing a slurry and see how much actual yeast you get, maybe you're not really overpitching. Even if it's a yeast you weren't planning to reuse; harrvest it and wash it to see how much is actually yeast and how much is trub.

[Big Nake]

Try yeast washing a slurry and see how much actual yeast you get, maybe you're not really overpitching. Even if it's a yeast you weren't planning to reuse; harrvest it and wash it to see how much is actually yeast and how much is trub.

I looked into washing because so many brewers swore by it including Jamil. I would harvest my yeast in a starter flask and then add sterile (boiled/cooled) water to the flask, swirl it and then throw it in the fridge. You're supposed to see some stratification... liquid on top, yeast in the middle and break material/dead cells/hops on the bottom. I never really see any stratification at all except some liquid on the top. Maybe it's because I'm VERY careful about getting clear wort into my primary (I rack from brewpot to primary and I get clear wort about 90% of the way) so maybe I just don't have a lot of schputz in my harvested yeast. Plus... it's hard to pour off the liquid and just get good yeast without getting the bottom layer too. So basically I feel like I'm stabbing in the dark on the yeast washing thing.

[Big Nake]

Here's an example... tell me what you would do: You make a starter for some 1028, wait a day or 2 until it's active and pitch it into a 1.050 English Ale. You're careful to get mostly very clear wort into the primary... very little hop schputz or anything else. The primary runs for 10 days and you rack out of primary and harvested the yeast (1028 is a medium floccer, IIRC so the slurry may be a little "thinner")... you get about 700-800ml of slurry, throw it into a sanitized flask and throw it into the fridge. You're going to make another beer with it the next day so what do you do with that yeast? Pitch it all? Divide it into 2 or 3? Wash it and only pitch part of it, dumping the rest? Since the slurry may be thinner, you can assume that 100-200ml of that volume may be liquid that rises to the top.

[pete maz]

Jamil says that you always want the yeast to reproduce some amount because the reproduction actually produces flavors that beer drinkers find pleasant. If you pitch too much yeast, you may not get those flavors and the beer's profile may be flat.

Ding ding ding! I've really found this to be true with the more bold-flavored yeasts like the Belgians & Brits. I'm pretty sure in BLAM, Hieronymus talks about some Belgian brewers purposely underpitching a certain amount, to force the yeast to reproduce and create their estery profile. When brewing Belgians I'm usually torn between pitching big in order to maximize attenuation, and underpitching to get better flavor. I've used the entire yeast cake before, and had really poor results from a flavor standpoint.

...you get about 700-800ml of slurry, throw it into a sanitized flask and throw it into the fridge. You're going to make another beer with it the next day so what do you do with that yeast? Pitch it all? Divide it into 2 or 3? Wash it and only pitch part of it, dumping the rest?

I generally divide into 2 or 3 sanitized containers, around 3/4 cup each. If I'm brewing within a month or so I'll just pitch the entire 3/4 cup, or make a starter if it's been longer. I also have some small, sterile test tubes that I'll put around 50-60ml into for long-term storage.

[Jimmy James]

Good questions Ken, and I also question many practices such as forced aeration when fermenting smaller beers for the same reasons. I have seen publications in peer-reviewed journals that have demonstrated you can and do get different flavor profiles depending on pitching rates, oxygenation and such. My takeaway from one study was that over-pitching and oxygenation can lead to higher amounts of diacetyl, while having little to no effect on final gravity when compared to a standard pitch/fermentation of 20e6 cell/mL with nominal wort aeration. Total ester concentrations will be lower in fermentations with significantly higher pitching rates also.

[Big Nake]

PM: The 3/4ths cup seems to correspond to about 200ml which sounds more in line with what Jamil suggests. Thanks for the feedback.JJ: It does seem like all of these things are connected and it's always tough to tell what you're actually pitching and how healthy it is. It seems like my cleanest-tasting batches come directly from the starter and then they decline... sometimes.

[Jimmy James]

JJ: It does seem like all of these things are connected and it's always tough to tell what you're actually pitching and how healthy it is. It seems like my cleanest-tasting batches come directly from the starter and then they decline... sometimes.

I also don't wash my yeast. If it is suspect I toss it and buy another vial and get a starter going (if cells start to lyse they'll release all sorts of stuff that can be toxic to neighboring cells and trigger lysis, and on and on so if you see dark/black streaks or pockets in your slurry I say toss it). Like you, I pitch the same yeast 2 or 3 times on successive brews, this works good if you plan out your brewing a little. This way I don't store the yeast a long time. When it comes to recycling yeast I tend to think the less I handle it the better.

[beach]

In the past I've tried, and been reasonably succesful, at rinsing yeast cakes and collecting fairly clean yeast. Note I said rinsing, with sanitized H2O, not washing with acid. But, this always seemed to me to be the PERFECT place to introduce infection if you're not very careful with procedures and sanitizing/sterilizing. What I started doing was to grow a 1500-2000 ml starter and after 18-24 hrs, while the yeasties are still in suspension from the stir plate, I will pour off ~400 ml into a sterile jar. I then cap this jar lightly, for a few days then tighten, place it in the fridge and use it to make my next starter of that yeast. The remainder if the first starter then gets pitched into my preasent batch. Sometimes I cool it, decant the liquor, and pitch just yeast if I have the time.By doing this I end up with very clean little yeast cakes at the bottom of the storage jar (just an autoclaved pint mason jar.) Most of my beers are 1050-1060 OG so my starters tend to be closer to 2000 ml before I pour some off to save.FWIW I've used my fridge-store yeast as much as 5-months later and have had them take off in a starter just fine.Beach

[Big Nake]

Okay, so I 've been rinsing my yeast, not washing. I did this a number of times, but eventually concluded that I'm no clearer on what to pitch because I never saw any stratification in the yeast... just the separation of liquid and solids. When I was a newbie, all of the more experienced brewers said The more yeast the better! and I would save giant blobs of yeast in 22oz bottles and then pitch that whole amount. Many people also said that it's practically impossible to overpitch. I'm not sure what the definition of overpitching even is, but I think there's something to this. When making beers in the 1.050 range like I do, it doesn't seem necessary to pitch HUGE volumes of harvested yeast.

[beach]

I'll be quite candid Ken, I have no idea if I'm pitching too much, not enough, etc. I just build a starter like I explaned and I end up making beer. I would be kind of nice to have a clue. //okay so I've posted to this thread twice and I have yet to help you, sorry Ken, continue//

[Big Nake]

I'll be quite candid Ken, I have no idea if I'm pitching too much, not enough, etc. I just build a starter like I explaned and I end up making beer. I would be kind of nice to have a clue. //okay so I've posted to this thread twice and I have yet to help you, sorry Ken, continue//

Just posting to the thread has helped because sometimes I think I'm the only one thinking about this. I don't live in a laboratory and I don't have a microscope so I can't really know what's going on with my yeast. On one hand, I like to know what's going on, but if I hear too much gibberish regarding the deep science of yeast (or water, for that matter), I get bored and say, Screw it... let's just make beer! I probably need to go back and listen to the one Brewing Network show I have saved where they discuss yeast harvesting, etc. Definitely some good information there. Cheers.

[Thirsty]

I just finished reading George Fix's Principles of Brewing Science, and he points out all of things you mention Ken about over/underpitching. So the key is how much am I actually pitching? I feel there is a fine line between managing this properly and micromanaging this. When rinsing the yeast, there is going to, no matter how much you try, capture some dead yeast cells and trub. I would think that this would contribute to maybe 1/3 of the slurry volume. Some other cells may not be in best health as well. So I am of the school of trial and error, start with a standard volume for all slurries and pitch that- probably twice the volume of the original starter's slurry. Monitor the results and try 75% or 125% the next time if unhappy with the results and so on. I think if you start getting into flocculation rates and try to guess at the cell count- then you are diving into the micromanagement part, and you are right- it is homebrewing here! I personally swirl my cake with a little distilled water to loosen it, pour it all into a 60 oz glass sanitized beer pitcher, let it set overnight in the fridge, pour off the top clear beer, then pour the loose slurry into 2-3 mason jars. I let whatever sticks to the bottom of the pitcher stay without forcing it. After a few days my mason jars get about 3/4-inch of slurry, and I use one jar per 5 gallons of my next brew. That is my trial and error and it seems to work OK.

[Big Nake]

After a few days my mason jars get about 3/4-inch of slurry, and I use one jar per 5 gallons of my next brew.

This sounds like a good rule of thumb and it also sounds like quite a bit less than I would pitch on subsequent batches. One of the other things I read (on the topic of having the yeast reproduce) is that you will always get fresh, new cells that are in good health if you don't pitch the complete amount you need to ferment the batch. First off, this sounds iffy because I wonder if the newly produced cells could be in poor health if the overall colony was in bad shape. But all of this could also mean that underpitching is actually a good thing! Thanks for the replies guys... good stuff.

[zymot]

For a couple years I have been playing the contrary voice and questioned the maxim that monster-starters are required to make good beer. The "I make a 5 liter starter for my 5 gallon batches" type of thing. Save the replies everybody, I know all about the mrmalty.com calculator.Putting together the pieces that I believe to be true or observed, it did not make sense. Some of the pieces are:1- Many homebrewers (myslef included) get good to great results without any starter at all, just direct pitch a Wyeast smackpack or White Labs vial2- I know of tests where 10 gallons of wort was split. 5 gallons got a full starter dose of yeast, 5 gallons got direct pitched.No difference was detected in the finished beer.3- Jamil in his recipe book typically specs ~2 vials for moderate ales. About the same as a 2 liter starter produces.4- Jamil also warns that as little as a 20% excess might be over pitching and can start to affect the beer flavor adversely.5- Yeast grown in a professional lab as supplied from Wyeast and White Labs is different than yeast harvested from a batch of beer. These two sources should not be considered the same and a yeast growth calculators such as mrmalty should not be applied to lab grown yeast.6- mrmalty and wyeast's online calculator agree that propagating yeast in a flask has a growth curve of diminishing returns. i.e. 2x the starter size may not return 2x the yeast cell count.7- I have experimented with using yeast cakes harvested yeast from previous batches. The beer produced seemed sort of lame and lifeless, not much beer character. These beers typically get back some life with extended aging. Note: this anecdotal and it is possible that this is all in my head.So what do I do? I made couple stirplates because it was fun. When I use liquid yeast, I make 2 ea 800 ml starters and split the vial between the two. For an ale with a moderate OG, I would not be afraid to direct pitch a single vial or smackpack. It is not optimum, but none of my homebrewing process is optimum.zymot's universal homebrewers advice: Do the best you can with the resources available to you. Enjoy the process and the beer you brew. Your beer will be fine.zymot

[ThroatwobblerMangrove]

1- Many homebrewers (myslef included) get good to great results without any starter at all, just direct pitch a Wyeast smackpack or White Labs vial2- I know of tests where 10 gallons of wort was split. 5 gallons got a full starter dose of yeast, 5 gallons got direct pitched.No difference was detected in the finished beer.

I usually make normal sized (2-3L) starters but sometimes I want the extra security that extra yeast is going to provide. Higher OG wort, lower attenuating yeast, cooler fermentation temperatures, non-ideal oxygenation methods, older yeast - these are all factors that if they weren't there I pretty much agree with you but if you start stressing the yeast out the more you start out with the better off you are. It's a matter of statistics and how much risk you are willing to take.

[Howie]

I probably need to go back and listen to the one Brewing Network show I have saved where they discuss yeast harvesting, etc. Definitely some good information there. Cheers.

Yeah, I was going to suggest that. There are two good episodes of Brew Strong that relate to this. One is on repitching yeast and one is on washing/rinsing yeast.