Do I Want to Ferment on the Grain or Off the Grain?

Fermentation on or off the grain has been a debated though out the distilling community many times. There are a couple of philosophies on why on the grain fermentation should or should not be implemented in a whiskey program.

Dollars & Cents

Let’s start from the business end of the spirit production process. First of all, implementing either philosophy will require the correct tools for optimal production speed and material handling efforts. 

Secondly, not all grains can be treated the same way in order to optimize sugar yield. Some grains, like corn have to be exposed to a higher amount of heat for a longer period of time in order to get optimal conversion. The result from this extra exposure to heat is that the grain solids of corn can become very pudding-like and viscus. And therefore, far more difficult to strain the liquid out of the solids. And so here is where grain in fermentation can help relieve some of the frustration of handling corn. Basically, we would be eliminating some of the materials handling steps more common with barley for example.

Also, because corn wort can be so viscus and difficult to strain out the liquid, fermenting (and distilling) on the grain also represents an increase in yield because we can be assured that any (converted) liquid absorbed by the grain solids will also contribute to alcohol yield during fermentation and during the distillation process.

The above is a long winded way of saying that with the right equipment, grain in fermentation to some degree can represent a cost savings on material handling, and an increase in yield compared to straining the liquid out of grain in solids.

Sensory

Distillers often debate weather or not grain in fermentation (and distilling) makes a more flavorful whiskey or makes for more acrid qualities in the whiskey?

Many distillers and enthusiasts alike claim they can’t really find any difference between either method.

Some distillers absolutely swear that grain in solids do install a bitter quality into the finished spirit. 

Other distillers insist that grain in solids contribute to the installation of a more desirable flavor complexity and mouth feel.

As a matter of fact, Todd Leopold from Leopold Brothers absolutely makes a very compelling argument that grain in solids distilled with an added measure of pressure from his 3 chamber still allows more oils found in the grains to be carried over into the finished spirit and therefore provide a more flavorful whiskey.

In the end It is up to you to determine what best suits your processing capabilities as well as your sensory preferences.