Maischewerk Restart Set for Stuck Fermentation: Sparkling Wine Yeast, Fermentation Aid, Combined Yeast Nutrient, Yeast Nutrient Salt

Your batch has stopped bubbling even though it still tastes sweet? A stuck fermentation usually has simple causes: too cold, too few nutrients or an exhausted yeast. This set contains the agents for a restart. There is no guarantee that every fermentation will start up again; with fresh, robust yeast and good preparation, however, the chances are good.

The sparkling wine yeast is bred for the second fermentation and, according to the manufacturer, is alcohol-tolerant up to about 16 % vol, so it also copes with a wine that already contains alcohol. The fermentation aid made from yeast autolysate gives the yeast better starting conditions and, according to the manufacturer, ensures stable cell walls, even at a high alcohol content. The combined yeast nutrient supplies nitrogen from DAP, inactive yeasts and vitamin B1. You only use the yeast nutrient salt (pure DAP) if less than half of the sugar has been fermented; in a wine that has already largely fermented, the yeast hardly takes it up anymore.

Included in the set

• 1 × Joenos Champagne/Sparkling Wine Pure Culture Yeast, 5 g for 10-50 l (Item no. SKU-103588): robust pure culture yeast, according to the manufacturer up to 16 % vol; place the fermentation vessel at 15 to 20 °C.
• 1 × Joenos Fermstart Easy, 5 g Fermentation Aid for Wine Fermentation (Item no. SKU-100919): fermentation aid made from yeast autolysate, 2 to 5 g per 10 liters, suspend in 10 times the amount of water before adding the yeast.
• 1 × Joenos Yeast Nutrient Complex 10 g for Fermentation Support (Item no. SKU-111675): combined preparation of DAP, inactive yeasts, cellulose and vitamin B1, at most 12 g per 10 liters.
• 1 × Joenos Yeast Nutrient Salt 10 g, Diammonium Phosphate for the Fermentation Start (Item no. SKU-100222): pure diammonium phosphate, only for a fermentation that stalls early; the pack states 10 g for about 10 liters, we recommend 3 g per 10 liters.

How to proceed

1. Put the batch in a place at 18 to 20 °C and wait until it has reached this temperature.
2. Suspend the fermentation aid in 10 times the amount of water and add it to the batch, dosage according to the package instructions.
3. Suspend the combined yeast nutrient in 10 times the amount of wine or water and stir it in; add the yeast nutrient salt only if more than half of the sugar is still left.
4. Let the sparkling wine yeast swell for about 20 minutes, at most 45 minutes, in ten times its volume of water at 35–40 °C, then gradually add some of the wine so that it acclimatizes. When adding, the temperature difference to the fermenting liquid should be no more than 5 to 10 °C; the pack still states 125 ml of water at 30–35 °C (an older recommendation) and a difference of at most 2 °C; the 2 °C is stricter than necessary and does no harm.
5. Add the yeast starter to the wine and watch the airlock.

According to the manufacturer, the yeast is enough for 10 to 50 liters, the fermentation aid, at 2 to 5 g per 10 liters, for 10 to 25 liters, and the yeast nutrient salt, at 3 g per 10 liters, for just over 30 liters; for the combined yeast nutrient, the manufacturer specifies a maximum amount of 12 g per 10 liters. The set is therefore sized for a stuck batch of up to about 25 liters. Not included are fermentation vessel, airlock and thermometer. What you can do if the fermentation behaves differently than expected is also covered in the free Maischewerk booklets at maischewerk.de/pages/anleitungen.