Fermenting procedures for taste rich products

Many believe that it’s the distillation procedure or equipment that defines how taste rich a product will be. But that’s only partially the case. What we distill, rather than how we distill, is the key. It is during fermentation that essential tastes are developed.

Distillation concentrates tastes and can help you get rid of some unwanted flavours. But if you have a poor tasting fermentation, distillation, by no means, is going to add great tastes!

My point being? If you are after a great tasting product, start by putting more effort in your fermentation procedures. Distillation does play a role, but it starts with fermentation.

What the starting-points to a great and taste rich fermentation are? Let’s dive in deeper!

Creating taste is about creating taste molecules. Taste molecules are also called “esters” and the process by which they are formed is called “esterification”.

Esters are formed when organic (carbon) molecules react with alcohol. And for esterification to take place effectively, a sour environment is needed. What’s also important is that chemical reactions – and that’s what esterification is – take place at a much faster rate in warmer environments.

So, if we want to make taste rich product, and aim for the best whiskey, brandy, or rum, and if we want to focus on our fermentation procedures, these are the ingredients we need:

  • Alcohol;
  • Organic molecules;
  • Sour and hot environment.

Alcohol forms during fermentation. In the beginning there is no alcohol in the fermentation, towards the end there’s more and more of it. This gradual increase of the alcohol percentage has to be taken into account. Don’t crash cool a ferment, because your distillation scheme says you need a wash. Rather, give it time to ferment dry. Most esters (due to the increasing alcohol percentage) are formed in the last two days of the fermentation, so don’t rush things.

Organic molecules are introduced into the fermentation by the fruits or grains the sugars are extracted from. So if you are after taste rich product, what you want to do is ferment “on the grain” or “on the pulp”. Don’t ferment clear beers, ferment dirty uncleared beers and wines. If “beer” and “wine” we can call it.

Also, a lot of organic molecules are introduced by the yeast itsself, during the aerobic, reproductive, cell wall build-up phase. This is important: for maximum taste, you want the yeast to have an aerobic phase. You can achieve this by, prior to pitching the yeast, aeriating the wash. Stir it. Add bubbles to it. Pitch a relatively low amount of yeast (no problem, since they reproduce during this first aerobic phase). Do not use a yeast starter.

The third “ingredient” to a perfect, taste rich ferment is an environment where the yeast and esterification process benefit the most. Hot and sour.

Higher fermentation temperatures like 28 to 34 degrees C are fine. And a lower pH of around 4.0 helps the esterification process a lot.

Fermenting with a yeast strain that works good in high temperature environments is a prerequisit. Actually, most baker’s yeasts work very well under these conditions. No need to go all fancy with expensive yeast strains, when  cheap and readily available baker’s yeast is doing a great job.

The sourness can be managed by adding backset from a previous strip run to the new fermentation. Backset plays an essential role in both rum and whiskey making. Backset makes the fermentation sour, which helps the formation of esters. Backset is also full of taste, nutrients, and organic compounds. If pH drops too much (under 3.5), use bicarb to up the the pH. Or turn it around: add even more bicarb, when starting up a new fermentation, so you can add more backset for even more taste transfer and more of the much needed organic compounds for maximum esterification.

To sumarize, the starting-points for taste rich fermentations are:

  • Use backset to sour up the next fermentation;
  • Keep the ferment at or slightly under pH 4.0;
  • Add oxygen, prior to starting up a new batch;
  • Add a relatievely small amount of yeast;
  • Ferment on the grain;
  • Ferment between 28 and 34 degrees C.

Are you interested in how you should ferment when aiming for a vodka? Keep following the iStill Blog. We’ll talk about that in a few days time!



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