Dry yeast reuse

[john luc]

There is an old saying that paper never refuses ink so applying that to the modern technology of the day, the internet never refuses comment. With that said I'm looking at reusing a slurry from a dried yeast I will pitch in a Lager. I am reading in some comments that dried yeast does not liked to be washed as the drying process has changed it nature. Anyone got a view.

[Jim]

The only view I have is that dried yeast is fairly cheap and ingredients for beer relatively expensive, so: is it really worth it?

[Meatymc]

I have saved samples from an S05/Proper Job scavenged combination and am producing the best beer I've ever done with it - I use IPA's method of taking a sample from the fermenter after 3 days, putting an airlock on it until it's finished then seal and put at the back of the fridge. I know from my notes that I'm on the 5th generation of 1 particularly sample and seen no reduction in quality in the finished product - my go too IPA recipe.

The only view I have is that dried yeast is fairly cheap and ingredients for beer relatively expensive, so: is it really worth it?

Whilst I agree to some extent Jim, I haven't got a field so have to buy malt but grow my own hops (wish they'd release citra!) and am happy to cut out the cost of yeast as well where possible. Having said that, I am a Yorkshireman through and through

[Robwalkeragain]

I’d agree the cost is prohibitive really but from a learning perspective I’d say go for it.
Washing won’t alter the yeast much, the idea is to use an acid strong enough to kill microbes but weak enough to leave the yeast unharmed as the cell walls are thicker. It will however mutate after every fermentation, which can alter flavour, flocculation, attenuation etc. it’s generally recommended to reuse 6 times but a lot of brewers have kept theirs going for generations.

[IPA]

I have saved samples from an S05/Proper Job scavenged combination and am producing the best beer I've ever done with it - I use IPA's method of taking a sample from the fermenter after 3 days, putting an airlock on it until it's finished then seal and put at the back of the fridge. I know from my notes that I'm on the 5th generation of 1 particularly sample and seen no reduction in quality in the finished product - my go too IPA recipe.

The only view I have is that dried yeast is fairly cheap and ingredients for beer relatively expensive, so: is it really worth it?

Whilst I agree to some extent Jim, I haven't got a field so have to buy malt but grow my own hops (wish they'd release citra!) and am happy to cut out the cost of yeast as well where possible. Having said that, I am a Yorkshireman through and through

Because liquid yeast is the biggest single cost in brewing is one reason I developed my method of saving it. I have one example that is now six years old. There is absolutely no reason not to use it for dried yeast.

[Jim]

Yeah, I've done it with liquid yeast - definitely worth it for the cost of that stuff.

And if you want to learn the skills of re-pitching and managing yeast, why not start with dried yeast?

[Kev888]

There is an old saying that paper never refuses ink so applying that to the modern technology of the day, the internet never refuses comment. With that said I'm looking at reusing a slurry from a dried yeast I will pitch in a Lager. I am reading in some comments that dried yeast does not liked to be washed as the drying process has changed it nature. Anyone got a view.

As I understand it, the acids used in yeast washing are not really ideal for yeast in general, though I don't know if previously dried (and now wet) types are any worse. The effectiveness of the wash is somewhat uncertain too, so all in all if it has got to the stage where washing is thought necessary then for an easily replaceable dried strain I just wouldn't go there. Though perhaps if it had been re-used so many times that it is no longer like the original, that might be different.

[Rookie]

FWIW I read a post claiming that once you ferment a batch with dry yeast you can reuse it just like liquid yeast.

[steviebobs83]

I've washed both types and never noticed a difference in quality. I've also done a modest gravity ale and then chucked a high gravity wort straight onto the slurry without washing and it took off like a rocket with no noticeable dip in quality (both were quite low hopped FWIW).

[a-slayer]

I often reuse the yeast from a brew made with Gervin/Nottingham dried yeast to ferment the next brew, works a treat. I don't wash it, just use the yeast slurry.

[Kingfisher4]

Yeah, I've done it with liquid yeast - definitely worth it for the cost of that stuff.

And if you want to learn the skills of re-pitching and managing yeast, why not start with dried yeast?

My plan exactly Jim. Will try IPAs method, probably with my first brew using new Grainfather conical next week. A couple of sachets of the more expensive dried mangrove jacks varieties can be £6-7 so not entirely insignificant.

Would it be best to take the sample at three days from the conical sampling port at the base, after dumping the trub etc or does it have to be top sampled? I’m guessing that the fermentation should be so active that the optimal live yeast will be well mixed at that stage?

[CestrIan]

I always re-use my yeast for 5 or 6 brews at least. Never had a problem and I've been doing it for years. I don't wash with acid, I just wash with water; that is, I add water to the yeast cake in the FV after racking the beer off. Give it a swirl to get it the yeast back in suspension, then leave it to settle for 5-10 minutes then pour off the yeast that's still suspended into a sanitised kilner jar. This leaves the dead yeast, any transferred trub or hop debris in the bottom of the FV. You can repeat this with the transferred yeast in the jar to wash again, but I don't think it's necessary, unless you dry hopped in the FV. Then store the jar in the fridge for the next brew.

Would it be best to take the sample at three days from the conical sampling port at the base, after dumping the trub etc or does it have to be top sampled? I’m guessing that the fermentation should be so active that the optimal live yeast will be well mixed at that stage?

I would wait until the brew has finished fermenting after a week or so, then cool to 10-11C for 48 hours. Then pull off the yeast from the bottom of the FV after ditching the trub. I've tried top cropping in the past, but I think you just risk adding infection to your brew for very little benefit.

[IPA]

Yeah, I've done it with liquid yeast - definitely worth it for the cost of that stuff.

And if you want to learn the skills of re-pitching and managing yeast, why not start with dried yeast?

My plan exactly Jim. Will try IPAs method, probably with my first brew using new Grainfather conical next week. A couple of sachets of the more expensive dried mangrove jacks varieties can be £6-7 so not entirely insignificant.

Would it be best to take the sample at three days from the conical sampling port at the base, after dumping the trub etc or does it have to be top sampled? I’m guessing that the fermentation should be so active that the optimal live yeast will be well mixed at that stage?

36 hours after the krausen has formed is a good time to take the sample and the sample should be fermenting wort from below the krausent not yeast deposited on the bottom or the yeast floating on the top.

[john luc]

What if it's a bottom fermenting lager yeast

[Kev888]

Some of the posts above have highlighted a confusion which might explain varying opinions on this general subject. Yeast washing (with acid) and yeast rinsing (with water) are very different things with different degrees of stress for the yeast, but if you try to do research around homebrew forums, people tend to confuse them.

Yeast washing uses acid in an attempt to do away with foreign bacteria and perhaps weaker yeast cells, it is something of a war of attrition. By contrast rinsing with water just floats out unnecessary physical matter, which is of debatable benefit in many cases but at least it isn't particularly harmful - the yeast just won't keep as well in water as they do in the beer they created.


Going off on the above tangent: Personally I prefer top cropping or collecting thick slurry if possible, but the method described by IPA works too. It automatically keeps the yeast fairly clean and happy - in the beery environment they naturally create for themselves and then settle down in; there is no urge to rinse it away for psychological reasons etc. Whilst the beer is fermenting actively, the live yeast cells are suspended throughout the beer so top or bottom cropping strains are both applicable to the method. Some old strains that are especially prone to floating in the krausen might benefit from being beaten back in to get a good cell count, but this would be done for the fermentation in any case.