Should I wash yeast or just pitch on top of cake?

Hi,

I know there are many topics relating to washing yeast and pitching on top of an exisiting cake and honestly I can't figure out which is best.

Here's the situation: I brewed an ESB about 3 weeks ago and plan on doing an almost dead replica recipe with the exception of I'm trying different hops in this one. It sounds like a no-brainer and I should just pitch on top of the existing cake but then others state that it better to wash the yeast due to fears of over-pitching and the fact that the beer will be darker. I have never reused yeast before for fear of contamination but now that I have a number of brews under my belt I'm confident all is well in that department.

What do you guys recommend?

Oh, and the yeast is White Labs 002 / English Ale yeast if that is of any help.

Thanks!

Eric

eric, another option would be to dump out roughly half of what you've got there and just use the other half to brew with. that way you're not over pitching and if it's a normal gravity ESB, that'll be too much yeast. i'd just swirl the hell out of it and dump half (or 1/3) into your new fermenter, slap an airlock on and call it a day. then you can try washing the other half if you're so inclined, but i've heard the 002 is difficult to wash because it flocculates so quick.

android said:

eric, another option would be to dump out roughly half of what you've got there and just use the other half to brew with. that way you're not over pitching and if it's a normal gravity ESB, that'll be too much yeast. i'd just swirl the hell out of it and dump half (or 1/3) into your new fermenter, slap an airlock on and call it a day. then you can try washing the other half if you're so inclined, but i've heard the 002 is difficult to wash because it flocculates so quick.

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I agree with this and would second the thought of only using 1/3 of the existing yeast cake. (Yeast tend to replicate 3 to 5 times when correctly pitched, so in the same gravity beer, you would want to use 1/3 to 1/5 of the yeast.)

Also, wlp002 is very hard to wash, but if you are going to use it within 1-2 weeks, you can probably get away with not thoroughly washing it.

I am about to do something very similar and I would say use the process you feel most comfortable with. I usually wash the yeast because I want to make note of exact pitching rates and don't want off flavors from previous batches trub. Also, I can get enough yeast for another 1-2 batches that will keep for a few weeks. If you are very careful about your sanitation, you will probably get by going either way (lots of people do). Good luck!

A lazy guy speaks: pitching on the cake is just sooo eeaasy. You don't have to clean or sanitize anything.

However beyond this obvious observation, I definitely do not have any argument with the factors & issues mentioned by the other posters.

And I did wask my first yeast the other day, and made my first starter yesterday!

Thanks guys. I think my long term plan is to get a yeast bank going using fresh yeast; for this batch I think I'll just use a new vial and be done with it. I really don't want to risk $40 worth of ingredients by trying to be cheap. The best that can happen is a normal batch while there are a number of negatives that happen.

Eric

i wouldn't call it trying to be cheap. many people claim huge benefits from using the same batch of yeast repeatedly. stronger fermentations, healthier yeast. if you are ready to pitch some of the yeast to your new brew within a few hours of racking the beer off the yeast cake (replace the airlock or use some sanitized foil to cover while waiting), i think you'll have VERY little chance of infection. you can put the new beer in a new fermenter, swirl up the yeast cake with a little bit of beer leftover and pour 1/3 or so of it into the new beer. i bet you'll have fermentation within 3-5 hours, which helps eliminate the chance for infection... but if you're feeling safe with just getting a new vial, of course go that route.

I agree with Android. Pitching on the cake is IMO risk free, totally easy, and probably gives a better result than using new yeast.

This is not to suggest that the other more advanced or labor intensive methods mentioned above are not better overall than pitching on the cake, rather just to say that if you don't do anything else, give pitching on the cake a try.

I would think that pitching on the cake is probably the least risky approach as well from a sanitation perspective, since you are not introducing any new steps or containers -- of course as long as the previous batch of beer was not infected.