Lab Methods and Supplies: Forced Fermentation

Method for Forced Fermentations


1) Aseptically transfer 500ml of wort to sterile flask.
2) Transfer enough wort to a hydrometer jar and measure the original gravity.
3) Label the flask and swirl vigorously 10 times prior to pitching to aerate.
4) Aseptically add 5mls of slurry, and swirl gently to mix.
5) Loosen cap slightly and incubate at room temperature.
6) After 24 hours, remove enough of fermenting wort for a hydrometer reading. Decarbonate samples by shaking, if necessary.
7) Record the gravity reading.
8) Repeat at 48 hours (taking two measurements) and 72 hours (one measurement), if necessary.

*Look for 50% Attenuation within 24 hours. A fermentation can be considered sluggish if 50% Attenuation has not been achieved by 48 hour measurement.


Below are the items needed to conduct Forced Fermentations

LW2110 1000ml Erlenmyer Flask
LW2110-S Size 9 stopper for 1000ml


Additional Requirements: 

Hydrometer, refractometer or densitometer

Ability to sanitize or sterilize the flasks 


Heated stir plate and stir bar