Turbo yeast - a definition
Turbo yeast is a mix of dry wine yeast (Saccharomyces Cerivisae) and nutrition. The particular strain used (there are many different strains of Saccharomyces Cerivisae) is chosen for its ability to produce alcohol and the nutrients are optimised for providing exactly the right combination of nitrogen, vitamins and trace minerals which the yeast needs in the different stages of alcohol fermentation. It also contains a pH adjustment as the pH of a sugar/water mix is far from optimal.
Different types of turbo yeasts
There are many ways of dividing the turbo's into classes, the most common are:
- Moderate alcohol (14%) - fast (1-3 days)
- High alcohol (20% or more) - but it takes longer, up to 5-7 days
- Temperature tolerant turbo yeasts
- Less temperature tolerant turbo yeasts
- Pure turbo's
- Normal turbo's
The fastest turbo yeast today is likely the Alcotec 24 (makes 14% alcohol from scratch in 24 hours) but in the "fast 14%" class you have a lot of different turbo's, many of them older recipes. The most extreme alcohol level today is produced by the Alcotec 23%.
Temperature tolerance mainly comes in if you ferment in warm climates or if you ferment more than 25 litres per batch. This is when the turbo yeast tends to overheat itself due to the internal heat generated during fermentation. The first turbo's such as Turbo3 and Alcotec 6 were not temperature tolerant - they work well on 25 litres but not if it gets very hot. Later recipes such as the popular Alcotec 48 are among the most temperature tolerant recipes there are. Alcotec 48 is the largest brand today because it can be used anywhere and still work well, even under difficult (=hot) circumstances.
The "Pure" turbo was invented rather late. The Alcotec 48 turbo yeast is the most well known of the "Pure's". It is a recipe especially developed for low levels of volatiles and off-flavours during fermentation. Pure fermentation has later been refined into perfection with the additions of Alcotec Triple Still and Vodka Star.
Raw materials for fermentation
All turbo yeasts of today are optimised for fermentation of a pure sugar/water solution. If you would like to use other sugars or materials containing sugar, such as molasses etc, you really need to use yeast packs specialised for these. The Alcotec Whisky Yeast can be used for molasses as it contains an enzyme, amylo-glucosidase, which will break down the starch into fermentable sugar. Without this, you would get a lot of starch left at the end of fermentation and you would have quality problems.
The recipes normally refer to plain white (beet or sugar cane) sugar. You can also use "Brewing Sugar", also known chemically as Dextrose Monohydrate. Plain white sugar actually will break down into this as one of the steps of fermentation, so by using Dextrose, you save the yeast some effort. It is also easier to dissolve because it already contains one water molecule (the Monohydrate bit). However, you need to compensate for this when you add the sugar. Because some of it actually is water, you need to add a bit more. A simple rule is: Add 10%. It is not exactly right, but it is good enough for practical use.