Fermentation

Procedure:
1. Add 50 ppm SO2 (red), 30 ppm SO2 (white)
2. Keep tank @ 50F
3. Pre-inoculation panel: YAN, Brix, etc
4. Calculate acid, water or de-acid addition
5. Cold soak (variable number of days)
6. Raise tank temp to 75F(red).
7. Calculate N addition for three part add.
Yeast w/ high N requirement or Brix > 25.5 ::: (325 ppm – ETS) = (DAP + SF + VMX) / 3
Yeast w/ low N requirement ::: (275 ppm – ETS) = (DAP + SF + VMX) / 3
8. Make additions at appropriate stage
Lag (0-6 hrs) ::: hydrated yeast (1.5-2#/K) + hydration minerals
Expon (6-12 hrs, 66% Brix) ::: SF + VMX + oxygen
End of exp (33% Brix, > 10 Brix)::: SF + VMX + oxygen + yeast hulls
Death ::: yeast hulls or SIY33
9. Punchdowns or pumpovers (3x/day during ferm)

SF= superfood, DAP = diammonium phosphate, VMX = Vitamix

Notes to self:
* requirements: sterols and fatty acids and oxygen for membrane growth
* NH3 becomes ethyl carbamate, or spoilage orgs eat it
* DAP toxic to membranes during hydration
* yeast hulls in all products, make sure addn 85°F more sensitive to alcohol toxicity, < below 55 slows yeast growth
* temp options: glycol, delestage (rack and return) cool down, indoor tank,
* O2 options: (build sterols) aerative pump overs for reds or sparging stones or conservative venturi “pump throughs” (closed pump over) for whites

Further reading:
Crowe, Alison, “Avoiding Stuck Fermentations”
L.F. Bisson, “Stuck and Sluggish Fermentation” (AJEV 50:1, 107-199)
J. Eglinton and P. Henschke, “The Effect of High Concentration of Acetic Acid on the Restarting of a Stuck Ferment” (Australian and New Zealand Wine Industry Journal, 1999).

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