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DAP toxic?

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Tall Grass

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Scanning through a few supplier websites this evening and I ran across this and it has me wondering...

DIAMMONIUM PHOSPHATE (DAP) (Nutrient)
DAP usage is 1/2 pounds per 1000 gallons
1.13 grams per 5 gallons
1.13 grams is about a heaping 1/4 teaspoon PER 5 gallons Add at 1/3 sugar depletion as it can be toxic to the yeast if added during the yeast re-hydration stage and the early fermentation stage when the yeast population is low.
I've been adding DAP (nutrient) and energizer to my wines right at the beginning (before sprinkling the yeast on top.) But, could that combo be TOXIC to the yeast ? I've never had any problems doing it this way ....
 

Stu

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Tall Grass,

Adding DAP to the water that you rehydrate your yeast in is definitely toxic. When freeze-dried yeast are rehydrated they are unable to regulate what chemicals pass through their membranes, because the membranes are dessicated. Once the membranes are rehydrated they function normally and are able to regulate this flux, so anything in the yeast rehydration water goes directly inside the yeast cells.

There are some yeast-rehydration nutrients (Go-Ferm, FortiFerm) that are meant to be dissolved in the yeast rehydration water before the yeast are rehydrated. These chemicals give the yeast some increased protection in cases of high sugar / alcohol.

As for DAP additions early in fermentation, it's a good idea to add DAP a day or so after inoculating with yeast. Freshly inoculated yeast first acclimate to their high-sugar environment, then begin increasing their population before they begin fermentation (this is the lag phase.) Dried yeast have plenty of N available to them from the manufacturing process, so adding it early can make the concentration too high.

Also, adding DAP early can inadvertently feed wild or spoilage organisms.

If you're a wild-yeast fermentor (I fall into this category) you should wait until your Brix drops by about 10%, then make your DAP / nutrient adds.

Good luck!

Stu
 

Wade E

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I dont use it with my rehydration water but do add it immediately with my must which I guess isnt the problem.
 

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