Washed yeast from a dark beer for future batches...

Hey guys,

This is an interesting one a friend in our homebrewers club posed to me the other day, and I've never had experience with it myself:

Say you wash your yeast off a batch, and that batch is a darker beer - in their case a robust porter - and plan to use that washed yeast again in possibly a lighter beer like a pale ale: would you have to worry too much about it darkening it up or changing the flavor? I told them if I was doing it I would decant almost all the dark liquid entirely, just enough to swirl up the slurry and pitch into a superlight DME starter and then decant off that as well before pitching onto a pale ale wort or anything that light, although I couldn't shed any light on whether or not it would affect the taste because I always harvest and use yeast light-to-dark and simple-to-complex, not the other way around.

Anyway, thoughts? Opinions? Experiences?

Just thought it was an interesting question. Personally I'd tend to think that there would definitely be some residual characteristics going from that dark to that light of a brew, but then again, if you're careful, maybe not?

I'd definitely expect some impact on the flavor, especially if any adjuncts were used at any point or dry hopping was going on in the primary. Generally, most people step up their yeasts by going from lightest beers to darker/higher ABV beers.

aiptasia said:

Generally, most people step up their yeasts by going from lightest beers to darker/higher ABV beers.

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Right - that's exactly my point. This is unusual that they're doing it sort of "backwards" so I was wanting to know if anyone had any experience with re-using their yeast in this particular way.

I do it all the time. I don't notice any flavor impact. I decant most of it off and dump out half the cake while I'm at it, but yeah it works well. I'd be more worried about gravity stressing the yeast than color or adjuncts.

from time to time i go to a Drake's brewery down the street from my house to get a flask filled with fresh yeast slurry. the last time i did it the only yeast they had ready was out of of a tank of porter. i was making a pale ale that day and used about 1/4 cup, maybe a little more in the pale ale. it was bubbling away that evening and the resulting beer had no hint of roastiness or any other flavor but the intended one. i let the slurry settle down and poured off the beer that forms over the yeast but the yeast i pitched was a dark brown.

masonsjax said:

I do it all the time. I don't notice any flavor impact. I decant most of it off and dump out half the cake while I'm at it, but yeah it works well. I'd be more worried about gravity stressing the yeast than color or adjuncts.

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eastoak said:

from time to time i go to a Drake's brewery down the street from my house to get a flask filled with fresh yeast slurry. the last time i did it the only yeast they had ready was out of of a tank of porter. i was making a pale ale that day and used about 1/4 cup, maybe a little more in the pale ale. it was bubbling away that evening and the resulting beer had no hint of roastiness or any other flavor but the intended one. i let the slurry settle down and poured off the beer that forms over the yeast but the yeast i pitched was a dark brown.

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Nice. Thanks guys! I will pass this along, although I think he probably already brewed and used the yeast anyway, regardless of hesitation. He's kind of a "screw it, it's good yeast..." kind of guy.

I took a few ounces of freshly harvested (not washed) cake from an oatmeal stout and dumped it straight into a nice light-colored IPA. No discernible impact on flavor or color.

Of course, it was a really, really flavorful IPA. I'd be hesitant about doing that where the second beer is a light, mild flavored cream ale or some such thing.

If it is really washed yeast per the title, I think that would have already answered the question. However, I suspect you are asking about slurry.

Just minimize the liquid carry over and you are fine.

For example, say you used 1 lb of dark or roasted malt in 5 gallons. You pull a pint of slurry. Assume half of that is beer flavored from the roast grains. This would mean you have 1/80 th of the original grains in it, or 1/5 th of an ounce carried over to the new beer. Some people add more than that to some of the lightest beers because the dark grains are supposed to help clear the beer. Try adding a half ounce of black to your next pale ale; you will not be able to detect it. If you let the slurry settle in the fridge for a few days, and decant the liquid, any flavor carry over will be a lot less.