Saccharomyces Yeast Rehydration

Last Updated: 6/2021

Applies to: wineries using Saccharomyces yeast. This protocol is not appropriate for non-Saccharomyces yeast. Contains a pdf download of the protocol above (including a calculations worksheet).

This protocol video is also available in in Spanish and French.


This protocol is NOT applicable to non-Saccharomyces yeasts. Please see our non-saccharomyces yeast rehydration protocol.

If you are using GO-FERM STEROL FLASH­™ as your rehydration nutrient, please follow this protocol.


Pro Tip: do this step in a vessel that can accommodate up to 4 times the volume of the rehydrated yeast.

step 1: Suspend 30 g/hL (2.5 lb/1000 gal) of GO-FERM PROTECT EVOLUTION™ or GO-FERM™ in 20 times its weight of clean, chlorine-free, 43°C (110°F) water. Please note that these rehydration nutrients do not fully dissolve into solution, some clumping is normal.

If not using a rehydration nutrient, add yeast to a water volume that is 10x the weight of the yeast at 40°C (104°F). This lower temperature is important, so you do not harm the yeast.

Rehydrate YEAST:

step 2: Allow temperature of yeast rehydration nutrient solution to drop to 40°C (104°F).
step 3: Add 25 g/hL (2 lb/1000 gal) of active dried yeast.

step 4: Stir gently to break up any clumps and let suspension stand for 20 minutes, then stir gently again. Foaming is not an indicator of yeast viability. Do not let yeast stand in rehydration water longer than 30 minutes without adding juice/must or populations will decline.


step 5: Slowly, over 5 minutes, add some juice/must to the yeast slurry to drop the temperature by 10°C (18°F). Let stand 15-20 minutes.

step 6: Repeat step 5 until the temperature difference between the yeast slurry and the juice/must is within 10°C (18°F). For example, if juice/must temperature is 20°C (68°F) and the yeast slurry temperature is 40°C (104°F), step 5 will need to be repeated twice.


step 7: Add yeast slurry from step 6 directly into juice/must and mix.

For large tanks with long filling times add the yeast slurry to the bottom of the fermentation vessel just as you begin filling with must/juice. This allows the yeast a head start over indigenous organisms.

pdf Download:

For a printable pdf download of the protocol above (including a calculations worksheet) please click below.