I just brewed a 10 gallon Black IPA that was split into two buckets and each fermented with US-05. The yeast cake after fermentation of each was insane. I was expecting a good amount of trub because of the amount of hops I used however I was not expecting to see almost a 1/2 gallon worth of trub. Appears the yeast attenuation on this batch was 82%. Which is high but not crazy. Also I've used 05 a few times before and never experience such a large cake as this. This got me thinking and I am wondering if there is a correlation between the amount of trub and the health of the fermentation. The larger the cake equals more yeast which indicates a healthy fermentation took place. Am I correct in my assumption?
How do you know that that the 1/2 gallon of sediment is yeast and not protein break and/or other types of trub? Maybe the cake is 1/2 yeast and half protein, hop particles (as you said), etc.
Sort of. A fermentation that produced more yeast than usual may indicate excessive oxygenation (though this is theoretically only possible if you are aerating with pure O2). As in you could have had an ideal fermentation with less oxygen and ended up with less yeast and less loss of beer. Does this mean your beer flavor is less than ideal? No, probably not. I would look at it as more of an efficiency thing in that the only real problem is that you lost a little more beer than you had to. Still, better to err on the side of too much O2 since you have much more unpleasant issues from under aeration.
Truthfully I don't. However by the looks of it my assumption is yeast is the major component as it was light brown and extremely smooth in appearance. Not much of the green gritty particles I expect from hop pellets. Interesting you mention oxygen…I do not have the ability to add pure oxygen however when I transferred the beer from my keggle to each of the buckets I did so outside on a very windy day. The stream of beer out of the ball valve was actually being pushed by the wind. There was a great deal of foam as it entered the bucket so I wonder if this would account for anything.
How much yeast did you pitch? I am inclined to think that you couldn't have over oxygenated in the circumstances you describe, even with the wind since my understanding is that you can't really overaerate even when directly injecting air with a pump, you need pure O2 to get levels that high. If you had a very high pitching rate, that could also have led to higher than normal levels of yeast production.
