ism which uses sugar to make energy for growth. If there is no oxygen around yeast cannot extract all the energy from sugar and throws out ethanol as a waste product.
To function, yeast also needs amino acids, enzymes and minerals, which collectively we call nutrients.
As well as throwing out ethanol as a waste product, yeast throws out another 1300 other compounds, which we can call "volatiles". These volatiles fall into chemical categories

* Higher alcohol’s (also called Fusel oils)
* Esters
* Carbonyl compounds
* Organic acids
* Sulphur compounds.

All fermented alcoholic drinks contain these volatiles, whether made in the home or made commercially. Indeed, it is basically the amounts and types of these volatiles that make, for example, dark Rum taste and smell like dark Rum or that makes whisky taste and smell like whisky.
It is important to make clean, pure ethanol in the home. We don't want these volatiles. Activated carbon is used after distillation to remove these volatiles. But, even the best activated carbons will not remove a large amount of volatiles, so it is important to try not to make them in the first place.
The choices of yeast strain and nutrients have the greatest influence on keeping volatile production to a minimum.

The only control you have is to buy a good Turbo sachet from a well-respected manufacturer. It is the Turbo manufacturers' job to select the best yeast strains for the job and use the correct nutrition. However, the temperature you use through out fermentation, and the activated carbon used all influence volatile concentration.

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Fermenting, continued
Turbo Yeast
Prestige Batch Yeast or Black Label yeast
Page 5 of 7

Use Prestige Batch yeast or Black Label yeast to make 14% ethanol in 3 days, use 1 sachet + 6 kg sugar in 25 liters or use 8 sachets + 48 kg sugar in 200 liters (or anything in between e.g. 5 sachets + 30 kg sugar in 125 liters etc).

Use Prestige Alcohol yeast 18% and Distillers yeast 18% to make 18% ethanol in 7 days, use 1 sachet + 8 kg sugar in 25 liters. We recommend you do not scale up to larger volumes unless you have good control of liquid temperature.

Prestige Batch yeast or Black Label yeast instructions for 25 liters.

1. You need a 30 liter sized plastic bucket. Clean it with hot water (it does not need to be sterilized unless it is very dirty).
2. Calibrate to 25 liters if it is not already graduated.
3. The point of this step is to end up with a final volume of 25 liters which contains 6-kg sugar and has a start liquid temperature of around 25-30°C.
4. First add either 5 liters boiling water or 10 liters hot water into the bucket. Add 6-kg ordinary white granulated sugar (sucrose) and stir until completely dissolved (about 2 minutes). Now top up to 25 liters with cold water and stir well for 2 minutes to ensure an even sugar solution. Ideally the cold water used for topping up should be between 15-20°C although water as low as 5°C can be used, this will just make the fermentation 1-2 days longer.
5. Add the sachet contents and continue to stir until no more particles of yeast are visible to the naked eye.
The liquid should have a milky appearance with no bits in it.
6. Now leave it at warm room temperature (around 20-25°C is best) to ferment for 3 days.
7. Any air temperature between 18°C and 30°C can be used but the time taken for fermentation will be different. At 30°C it will take only 2 days (but make more volatiles!) and at 18°C it will take 7 days.
8. After fermentation this "mash" should be distilled, diluted to 40 - 45% ethanol then passed through activated carbon to remove volatiles before adding essences. See elsewhere for further details.

A super trick to improve quality
When the mash has fermented completely (use a Hydrometer to check), wait until it is crystal clear. Then draw out the mash with a siphon, leaving all yeast and impurities in the fermentation vessel. By using this method you have a crystal clear mash without yeast to distill.

The mash should clear by it self in a day or two. You can speed this up by adding a clearing agent for wine or by placing the mash in a cold place. The mash must have fermented out completely before clearing.

If the mash is cloudy, it produces badly “off” taste when the cloudiness is heated, in contact the high temperature near the heather. To avoid this bitter taste, use crystal clear mash.

Heating more gently by adding 1-2 liter of rashig rings in the boiler to divide the heat can reduce the bitter taste. It can also be avoided by heat by a hot water jacket on the boiling vessel. This has the principle of a water bath, by using a jacketed tank for heating. It is the hot water that heats the mash, not the original heat source. The common is to distill a crystal clear mash.