Denard Brewing

Better brewing through science.

Stuck Fermentation Nuclear Option

It is inevitable that a mazer will run into a stuck fermentation. Sometimes it's due to extremely high SG, sometimes your postal service left your yeast in 105 degree heat for too long. It happens. A lot.

So, your stuck. "What now?" you ask. There are a few easy things to try before the nuclear option. This is for when the easy things didn't work. 
1. Go over to and pick up some Uvaferm 43 yeast. This yeast is the king of unsticking ferments. Tolerance is 18% ABV, so beware. Also get yeast hulls, GoFerm, and anything else you need. 
2. Add yeast hulls (aka ghosts; 20-30 gram per 5 gallons of must) to soak up toxins and stir. After a few days, rack off sediment. If necessary, dilute a bit with water to get your gravity is a reasonable range of <1.12. 
3. Make a starter as follows:
-Sanitize everything. 
-Rehydrate 20 grams of Uvaferm 43 in equal weight of GoFerm. 
-Add 6 oz of honey, water to slightly shy of 1 liter and the rehydrated yeast. 
-Add one cross shaped magnetic stir bar. 
-Stir on stir plates for 2-3 days. 
4. Acclimate starter. 
-Now add a cup of your stuck must to the starter and give it a few hours. Make sure it is actively fermenting before you add more!
-Repeat until you have 2 liters. This process may take a day or two. 
5. Pitch starter into stuck must. You should see the gravity drop a bit in the first few days, then really take off. 
6. Pray. Because if this doesn't work,  nothing else will. 
by denardb on July 15, 2015, 1:22 a.m.