Using same yeast cake for multiple batches

[erikhild59]

I have begun a 5 batch cycle which I am fermenting in the same primary on the same yeast cake(white labs american ale).I'm giving each 1 week primary and 1 week secondary give or take a few days. My primary concerns were ~a~ will the primary remain sanitary and -b- will I be massively overpitching on the last 3 batches?Anyone else ever done this? Any advice/comments?

 

[cvstrat]

You're dumping sanitary wort into the carboy and sealing it up, there's no reason it shouldn't remain sanitary.

Since you are only fermenting for a week each, you shouldn't really have any problems at all. Just remember that all the hops and other particulate is left behind each batch in the primary, along with some amount of beer. This could slightly alter the color of your beer if they mix. I pitched apfelwein directly onto an american stout yeast cake and it was awesome.

The yeast don't keep reproducing simply because we put fresh wort in the carboy. After the first batch you'll have the right amount of yeast to start fermenting immediately. There will be almost no lag time at all. If you haven't been using starters, batches 2-5 might be the first time you've actually pitched ENOUGH yeast. Might want to use a blow off valve if you don't already.

 

[erikhild59]

Good to hear...I brewed batch 4 last night and it was actively fermenting in 30 minutes!Never seen such a quick start. I will post results as I drink them

 

[erikhild59]

And the blowoff has been ridiculous!

 

[Hex]

I'm ready to bottle my second ten gallon batch. The first was two carboys filled with Yeoman's Special Bitters, and different yeast (WY1968 and WY1275). The second two were put on top of the first's yeast cakes, they are IPAs. I let each batch sit on the primary for 21 days each, and dry hops in the secondary for two weeks before bottling, so in approximately two months, I've got twenty gallons of beer on the wall! I will definitely do this practice again.

 

[Big_Belgian]

Just curious if there is a good discussion here as to how this process is carried out. Do you rack the old brew off the trub first, then brew and transfer the new cooled wort directly into the same carboy later that day? Do you "wash" the yeast cake or do anything to it while its sitting there in the carboy waiting on the fresh wort?

 

[Hex]

I transfer the first beer to secondary when the new batch is cooling after boil, then dump new batch directly on old yeast cake when it has cooled to pitching temperature. I can't remember if I aerate the second batch...

 

[andrew300]

It will work for sure. But it isn't the greatest decision if you want to make the best beer possible. You are pitching onto a yeast cake that has way to many cells as well as dead yeast and trub from the previous fermentation.

 

[Bradinator]

You're dumping sanitary wort into the carboy and sealing it up, there's no reason it shouldn't remain sanitary.

Since you are only fermenting for a week each, you shouldn't really have any problems at all. Just remember that all the hops and other particulate is left behind each batch in the primary, along with some amount of beer. This could slightly alter the color of your beer if they mix. I pitched apfelwein directly onto an american stout yeast cake and it was awesome.

Will it affect the overall flavour of the beer as well?

 

[Gremlyn]

Will it affect the overall flavour of the beer as well?

Certainly. Over pitching can lead to off flavours as easily as under pitching can. Rather than straight reuse the yeast cake, I recommend washing the yeast first and then repitching. That way you also get any of the old trub out that could also contribute flavours to the new beer you didn't want or expect.

You also start adding selective pressures to your yeast colony. Yeast with the ability to survive better in an over populated environment will stay alive while others will perish. You don't what other traits the yeast that are surviving have, they could be the yeast that are more prone to throwing off diacetyl or acetaldehyde and not cleaning it up later... Point being is that after a few batches on the same cake, you're risking having the yeast ferment completely differently than the first batch.

 

[permo]

Certainly. Over pitching can lead to off flavours as easily as under pitching can. Rather than straight reuse the yeast cake, I recommend washing the yeast first and then repitching. That way you also get any of the old trub out that could also contribute flavours to the new beer you didn't want or expect.

You also start adding selective pressures to your yeast colony. Yeast with the ability to survive better in an over populated environment will stay alive while others will perish. You don't what other traits the yeast that are surviving have, they could be the yeast that are more prone to throwing off diacetyl or acetaldehyde and not cleaning it up later... Point being is that after a few batches on the same cake, you're risking having the yeast ferment completely differently than the first batch.

+1

the only time I am a proponent of pitching on a cake is when it is calculated, like making a batch of 1.035OG Bitter and using that to pitch a big IPA unto......I did exactly this over over the weekend.

 

[SickTransitMundus]

It will work for sure. But it isn't the greatest decision if you want to make the best beer possible. You are pitching onto a yeast cake that has way to many cells as well as dead yeast and trub from the previous fermentation.

Exactly. I stopped repitching onto cakes after finding that my repitched batches often had off-flavors characteristic of overpitching. Wash your yeast or use fresh starters, and use the Mr Malty calculator. Your beer will be better for it.

http://www.mrmalty.com/calc/calc.html

 

[0110x011]

As far as the sanitation issue goes, the problem is that every beer is going to have bacteria in it to one degree or another. If you have good sanitation practices, the amount of said bacteria remains below the flavor threshold, and its growth is stunted by the introduction of alcohol. If you keep repitching onto the same yeast cake, what little bacteria is in that cake is allowed repeated opportunties to grow. So, you might not have a contamination issue for the first few batches, but the risk you will grows every time you pitch new wort onto that cake.

The other issue is flavor. Much of the flavor contribution from the yeast comes from the growth phase, and if the yeast doesn't have to grow, that flavor contribution will be lost.

I'd suggest washing the yeast and repitching from there. You can better control your pitching rate, and spot contamination faster.

 

[erikhild59]

To answer the procedure question, my method is to to rack the previous batch to secondary while I'm cooling the new batch of wort, so the carboy is only empty for a few minutes.I also dump any liquid remaining just prior to filling. So far I've only tried beer from the first batch (rye p a ) but will repost with taste notes from the next four batches.

 

[erikhild59]

Just a quick update on batches 1 and 2....#1 Rye PA -really good malt flavor ,big hop flavor and aroma , strong bitterness , overall pretty good, perhaps a bit high in ibu s but good.#2Caribou Slobber clone(all willamette hops)Wow! Great malt , roasty chocolate sweetness , just enough hop flavor.Love this beer....so far so good...

 

[erikhild59]

Batch#3 Black Ipa o.g 1.073 .f.g 1.014...well balanced for an Ipa, good roasty malt, coffeeish background , moderate bitterness upfront followed by good hop flavor , slight citrus aroma.My favorite so far....
p.s. its the Northern Brewer black ipa basically with a few tweaks.

 

[MachineShopBrewing]

.I'm giving each 1 week primary and 1 week secondary give or take a few days.

If you do this, you will be only selecting for the most flocculant cells. There will still be a lot of yeast in suspension after a week. By racking those off over and over and repitching onto the yeast that fell to the bottom, your beer will start to underattenuate and cause off-flavors in addition to those already stated by over pitching.

 

[erikhild59]

Yeah 1 week was a bit aggressive I agree . Batches 3 and 4 had 2 weeks primary minimum (#4 was 3 I think) but so far I think these beers are better than average for my system and #3 is maybe top 3 alltime, and no off flavors in any beers yet.I'm considering doing this regularly.

 

[erikhild59]

Batch #4 cream ale , crisp ,malty ,slightly sweet. Well carbonated, a guzzler. Unfortunately, this is the end of the cycle.too busy @ work to get to # 5 in a reasonable time, needed to be bottled.overall , no negatives, just good beers.I will take all given advice , especially selecting for flocculation.

 

[mcflyfisher]

I have done this same thing for years. My experience has been that this works out fine up to about 5 batches for Chico strain yeasts. I tried it with a heffe yeast and learnd that the second batch was so different that I didn't try a fourth. (Yes, by the time you realize the 2nd is off you have already started the 3rd.) It really works a lot better if you think your brew schedule through for this process. Each beer should increase in gravity. Color doesn't seem to matter as much as I thought it would. A good schedule is Cream Ale, APA, IPA, IIPA, Barley Wine. The scary part is that you are putting more and more expensive brews on top of the cake. Though it is true that you are adding contamination with every brew, you are also getting such quick alcohol production it seems to work out (that is just my theory I have no reference). For me, washing the yeast added another opportunity to increase contamination so I just kept pitching on top of the cake. Did I make the best beer I could have? I doubt it. Was it really good? Yeah I think so.
Currently I am not doing it quite this way. I am trying to make WLP007 my house strain, and I am am experimenting with different temps, and rates in order to figure out how best to do this.

 

[erikhild59]

Yeah , a lot of naysayers out there, but everyone out there that's actually done this says the same thing, that it works great , and I agree . I'm glad to see that you're experience with chico was positive through 5 batches, as I primarily use chico ,and 5 is about where I would start over.

 

[mummasan]

https://www.homebrewtalk.com/f163/why-not-pitch-your-yeast-cake-166221/

Read the first post in the linked thread. While it is possible to make beer by pitching directly on a yeast cake, why not try to make the best beer possible? The best thing about Bob's suggestion is that it takes very little effort and you pitch into a clean carboy or bucket.

 

[erikhild59]

Who says I'm not? I've seen no ill effects to suggest subpar quality. I'm completely happy with all the beer so far and will continue this method when I can. I may be starting another rotation this weekend and will post further...

 

[wilserbrewer]

Out of curiosity, how much yeast slurry is there after five batches? Huge I imagine.

 

[erikhild59]

Quite a bit , maybe 1 1/2 inches deep in the bottom of a 6.5 carboy, although much of that is trub/break material , so I guess its hard to say accurately. I will say that on the last batch, I had active fermentation in 45 minutes, and in 2 hrs the blowoff tube was in use.