Ferment Cycle

Oxygen Needs to be Added before Yeast

Yeast needs oxygen to reproduce.  Oxygen is essential right at the start of fermentation to enable the yeast to multiply, called budding.  This is the lag phase of fermenting. 

Use a fish bubbler to introduce oxygen throughout the liquid.  An alternate method is pouring the liquid several times from one container to another in a slow stream with a waterfall like appearance.

Do not blow through a tube into the liquid to airate.  That is carbon dioxide not oxygen.

Lag Period

This is a period of 2 to 3 hours where the yeast is multiplying through out the liquid.  Reproduction stops at 50 million cells per milliliter.  Any remaining oxygen in the mix will be carried away by the CO2 bubbles.  Any oxygen introduced after fermentation begins will oxidize and leave a stale taste in the mix — a ruined batch.  

Fermenting Process

Cool the liquid to 30C (86F) a little more than room temperature. The best temperature is stated on the yeast package.

Add yeast nutrient.  The nutrients are specific to the type of yeast used.

Add oxygen throughout the mash with a bubbler similar to what is used in a fish tank.

Yeast – Add hydrated yeast.  Stir thoroughly.  Put the sealed top on and the airlock bubbler in place.

Ferment the liquid at a constant 25C (77F).  One of the by products of fermenting is an abundance of CO2. This gas is released by your airlock.  When the airlock stops bubbling the fermentation is over and the yeast had died.  This can be from one week (average time) to two weeks depending on the yeast and the temperature.

The carbon-dioxide is heavier than oxygen and will cover the top of the liquid should there be a leak so the ferment will go on without unwanted bacteria getting in.

Anti-Foaming Agents

These break up the bubbles that lodge at the surface.  Fruits, grains, and molasses create big amount of foam and can outgrow the fermenting chamber if there is not enough head room.  

Stirring the Mash or Wash

Stirring the liquid once or twice with a sterilized stainless steel paddle will speed up the fermentation process insuring the yeast has access to all sugars.

Fermenting Finished

At this point the top of the fermented mash looks like a wart and hence the finished fermented liquid was called wart.

The yeast sediment collects on the bottom.  Siphon off the liquid in the ferment container carefully leaving the yeast sediment undisturbed on the bottom.  That bottom thick layer is yeast (not dead but dormant).  This slime like layer is to be thrown out.

Test for Potential Alcohol

A specific gravity test will determine the maximum ABV you will get after distilling.  Don’t use an acrylic test cylinder as the alcohol will deteriorate the plastic and plastic particles will enter your mix.  Be sure and adjust your reading based on the temperature of the liquid.  Hydrometers and Alcohol meters are calibrated at 60 F.   Subtract 1% ABV for every 5 F above and add 1% for every 5 F below calibrated temperature of the hydrometer.

Siphoning

Do not pout out the finished liquid.  Use a special tip at the end of your siphoning hose that will distance the end of the hose from the yeast.  Make sure to not disturb the yeast at the bottom.  Leave some liquid on top of the yeast to make sure no yeast is sucked out during the siphon process.  Use water if needed to prime the siphon hose.

CO2 Bubbles

There will be micro bubbles of CO2 still present in the present state of the mixture.  Gently shake the contents to help them CO2 to escape just like you would getting bubbles out of a coke.