Mead & wine
Questions for the panel:
1. Relating to mead/wine:
Many of the spoilage organisms die off or at least reach their stationary phase at 2 - 5% alcohol. So the sooner the added yeast can get through their lag phase and start growing and producing alcohol the sooner they will overwhelm the spoilage organisms and minimize their production of aromas and flavors. Some of these spoilage organisms produce compounds that add to the complexities of the wine when they are present in trace quantities but can become off flavors and aromas and even toxic to the added yeast if the added yeast does not over whelm them soon enough.
The sooner you get the added yeast through its lag phase and into its growth phase the safer you are. The added yeast produces 30+ times as much alcohol per yeast cell during its growth phase than it does during the stationary phase. You can keep it in its growth phase longer by proper rehydration (Go Ferm), nutrient addition and minimizing spoilage micro flora growth.
This information does not necessarily translate directly to all 5 – 10 gallon operations. However the principle of getting the adding yeast into the must or mead ASAP holds true. With good equipment cleaning and sanitizing practices, honey and grape concentrate offer very little spoilage micro flora problems. However, with frozen juice and whole berries there is always the possibility of spoilage organism problems.
2. Relating to mead/wine:
I've been reading that yeasts like nitrogen
from different sources during different phases in the early stages of
fermentation. I've seen recommendations for using DAP at the end of the
lag phase and Fermaid-K at the 1/3 sugar depletion phase. Does this play
a bigger role than
I wish that there was a universal protocol for the addition
of nutrients to all fermentations, but there isn't. There are too many
With good cleaning and sanitary practices, there is very
little problems of spoilage yeast with honey and concentrates. So, it
is safe to add the well balanced nutrient at the beginning of the fermentation
when the yeast needs all the nutrients and will not have to share them
with spoilage organisms. Then add DAP in increments during the growth
phase and into the beginning of the stationary phase. Yeast like a fresh
source of nitrogen during the growth phase and will reward you with minimum
production of H2S and a healthy cell through out the entire fermentation.
FAN or YAN in fresh grape juice can vary over a wide range depending on the grape varietal, vineyard practices and season from 40 PPM YAN to well over 500 PPM YAN. If you have the YAN analysis, these are our recommendations: http://www.lallemandwine.us/products/nutrient_strains.php
If you do not have a YAN analysis you should add 2 - 4 lbs. of DAP over the first 1/3 of the fermentation and 1 - 2 lbs of Fermaid K after 1/3 of the sugar has been converted to alcohol.3.
Oxygen should be considered as a yeast nutrient, so make sure that the yeast gets enough O2 near the end of its growth phase.
4. Potassium is a nutrient requirement that should be taken into consideration in honey, corn and cane sugar and grape concentrate fermentation. 1/2 to 1 lb of potassium carbonate should take care of this requirement added with in the first 12 hours of the fermentation.
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