Forced Fermentation Test

A forced fermentation test is performed to identify the final gravity/full attenuation potential of a wort sample and yeast culture. This is particularly helpful when developing new beer recipes, if there are changes in the mash profile, as well as working with new ingredients, including yeast.

The sample is held at a higher temperature and over-pitched to ensure complete attenuation is achieved before the production batch is finished. Analysis is performed by comparing the test’s attenuation potential to the production batch’s attenuation potential. In the case of slow or stalled fermentations, it can be used to identify if the issue arose from yeast health or brewhouse inefficiencies.

Results

• If there is a difference between forced fermentation and fermentor fermentation, it could indicate contamination or other yeast-related problems such as wort oxygenation, yeast health, or pitch rate.
• If both forced fermentation and fermentor fermentation are different from your expected calculated FG, it could indicate problems on the hot side, with mash temperature or other factors leading to a fermentation that does not contain enough fermentable sugars.