YEAST STUFF: SUPER NEAT & ONLY SORT-OF-TECHNICAL DATA
Sacch. Cerevisiae- most widely used yeast for fermentation.
Yeast populations survive winter kill in vineyard. #yeaststrong
Add pomace (leftovers after pressing aka skins/seeds) to vineyard to increase native yeast pop.
If we have yeast + grapes in vineyard why don’t grapes ferment on vine? Yeast can’t access sugar until juice is pressed.😲
Yeast only works on 6 carbon sugar (glucose, fructose). 5 carbon sugar molecules will not ferment to complete dryness.
Yeast need minerals like magnesium and potassium .
Yeast need nitrogen (they are made up of 25-60% N); lack of nitrogen will result in stuck fermentation😒
Yeast need vitamins just like people.
Yeast like fermentation temps 57-95.
Higher fermentation temps will increase rate of fermentation; however, slower fermentations are often desired to increase texture/flavor 🐢 🐢 🐢
You can crush grapes in advance of the main harvest to get a jump start on fermentation by increasing yeast population before primary.
Cultured yeast are not artificial and have been proven effective .
Native or “wild” yeast require more discretion.
Wild yeast will consume sugar immediately jump starting fermentation; cultured yeast when added will take the lead from there.
The sooner cultured yeast is added, the more control is had over the sterilization of the product (especially helpful in whites).
No such thing as a sterile must #life
Wild vs Cultured
greater potential aroma, flavor, textural complexities Wild
greater control, higher alcohol potential, wider range of fermentation temps Cult
tends to be fuller, rounder, softer Wild
clean, varietally correct, low odor Cult