mandoman
Well-Known Member
OK. I'm a convert. i believe everyone when they say we underpitch and we should pitch larger volumes of yeast using more dry yeast, or preferably, large starters from liquid yeasts at the 100 million cells per plato per ml or whatever. I get that. i also get that we should ferment in a primary for 10 days to 14 days, even longer, and that yeast should be oxygenated at the beginning of the ferment. What I don't get is how we ASSESS our fermentation.
The variables (responses) I see being used, and use myself, are quantitative and qualitative observations of the fermentation process. On the quantitative side we have gravity. We record starting gravity, we have an idea of what the finishing gravity will be, and we consider fermentation 'finished' when the FG is consistent for several days (does not decrease further). We also quantify temperature as being A) the right target (e.g., 68 for US 05) and B) consistent (i.e., the same temp the whole time, not up and down). Further, we observe qualitative parameters including: quick start of fermentation. Seems most people consider fermentation to be better if it starts quicker. Within 24 hrs is good, immediately is better. We also qualify things like fermentation 'activity' lots of airlock bubbling, churning of the beer in the fermenter, etc. are good things.
I'm sure I'm forgetting some things. But, having said these things we would consider a good fermentation to A) attenuate fully, B) adhere to consistent and correct temperature, and maybe C) require an approximate amount of time (e.g., 3-5 days for ale at XX OG, or 7-10 days for lager at XX OG) where more or less days to ferment could indicate something is wrong.
here's where I'm having trouble. I can seriously underpitch with say, one vial of WL 001 in a 1.070 pale ale and A) ferment at 68, B) completely attenuate at 4-5 days but leave in the fermenter until day 14, and C) aerate just by shaking or using an aerator attachment to end of cfc and get a great beer, right? We all have done this. I could also end up with some issues with this beer. For example, I just did essentially this brew and ended up with some diacetyl.
Now the confusion. I could also have done the same beer and aerated, pitched a large 4 L starter, and had consistent and correct temps. In other words, there would be no quantitative or qualitative differences in the fermentation process (e.g., temperature, attenuation, activity) to indicate a difference. Of course, the beer could have off-flavors LATER. Are there no ways to 'measure' a bad fermentation? I read a lot about beers 'not attenuating fully' or 'not finishing' or 'having a lag time before fermentation starts'. These are all solid observations that something is wrong with the process.
I guess what I'm looking for are the solid, observable, even quantifiable indications of less-than-desirable fermentation. Is it diacetyl? How do we 'KNOW' that aeration and temperature are so critical if there's no way of quantifying this????
I've seen the yeast life cycle things. I've read jamil and palmer and daniels. I've had microbiology. There is a lot of great information out there, don't get me wrong, but the fermentation thing seems a little hocus-pocusy for lack of a better term. Are we just trying to give the yeast what we 'think' they want - and how do we know what they want?
I'd be interesting in a discussion about this, or at least an education.
cb
The variables (responses) I see being used, and use myself, are quantitative and qualitative observations of the fermentation process. On the quantitative side we have gravity. We record starting gravity, we have an idea of what the finishing gravity will be, and we consider fermentation 'finished' when the FG is consistent for several days (does not decrease further). We also quantify temperature as being A) the right target (e.g., 68 for US 05) and B) consistent (i.e., the same temp the whole time, not up and down). Further, we observe qualitative parameters including: quick start of fermentation. Seems most people consider fermentation to be better if it starts quicker. Within 24 hrs is good, immediately is better. We also qualify things like fermentation 'activity' lots of airlock bubbling, churning of the beer in the fermenter, etc. are good things.
I'm sure I'm forgetting some things. But, having said these things we would consider a good fermentation to A) attenuate fully, B) adhere to consistent and correct temperature, and maybe C) require an approximate amount of time (e.g., 3-5 days for ale at XX OG, or 7-10 days for lager at XX OG) where more or less days to ferment could indicate something is wrong.
here's where I'm having trouble. I can seriously underpitch with say, one vial of WL 001 in a 1.070 pale ale and A) ferment at 68, B) completely attenuate at 4-5 days but leave in the fermenter until day 14, and C) aerate just by shaking or using an aerator attachment to end of cfc and get a great beer, right? We all have done this. I could also end up with some issues with this beer. For example, I just did essentially this brew and ended up with some diacetyl.
Now the confusion. I could also have done the same beer and aerated, pitched a large 4 L starter, and had consistent and correct temps. In other words, there would be no quantitative or qualitative differences in the fermentation process (e.g., temperature, attenuation, activity) to indicate a difference. Of course, the beer could have off-flavors LATER. Are there no ways to 'measure' a bad fermentation? I read a lot about beers 'not attenuating fully' or 'not finishing' or 'having a lag time before fermentation starts'. These are all solid observations that something is wrong with the process.
I guess what I'm looking for are the solid, observable, even quantifiable indications of less-than-desirable fermentation. Is it diacetyl? How do we 'KNOW' that aeration and temperature are so critical if there's no way of quantifying this????
I've seen the yeast life cycle things. I've read jamil and palmer and daniels. I've had microbiology. There is a lot of great information out there, don't get me wrong, but the fermentation thing seems a little hocus-pocusy for lack of a better term. Are we just trying to give the yeast what we 'think' they want - and how do we know what they want?
I'd be interesting in a discussion about this, or at least an education.
cb