View Full Version : Just a piece of interesting/worthless information. #2

01-18-2017, 10:18 AM
So if you plot a fermentation on a graph it has a bell type curve. I always thought that the tail end of things ( when it straighten out to a flatter profile) was because things slowed down while the yeast started bumping into the higher alcohol content. But them it dawned on me that the profile is very much the same on session meads at much lower ABV. So the only thing I could think of is that the bio mass is dying off faster than they are reproducing.

SO I asked the head wine maker/professor at The Robert Mondavi Institute At UC Davis about this. And he did say this was correct. It was a drop in biomass population.

I asked if it was due to food shortages, too much toxicity, overpopulation. Like many of my questions last week. They didn't have an answer. :(

01-19-2017, 12:13 PM
Yeast is a living thing.
I can't answer this with total certainty but I can give you some info
Yeast divides rapidly until it gets to the stationary phase. In that one the little beasties will hoard and compete for the food and some may divide and some may die. but that soon ends when there are not enough nutrients to live. That happens because the yeast have already hoarded all of the nitrogen usually and because glucose has run out and they have to eat fructose and other sugars. they metabolize those sugars slowly. So the drop is probably due to the fact that they take all the glucose and then when it runs out they start to die and only some survive. It is surely affected by the ABV and nitrogen, phosphate...I'd say its a mix of those reasons. Both wine and mead contain glucose and fructose as main sugars so this is a probable explanation.

As I said I cant be 100% certain but that'd be my guess
Edit: Also, try fermenting acacia honey. it has the highest fructose content in all the honeys. it starts fast and furious but then ferments slowly because the glucose runs out. I have seen this. actually if when that happens you add more honey the yeast starts to ferment fast again.