In one of the topics I wrote that I can post a recipe of Russian traditional distillate called “Bread wine” or “Polugar”. Very smooth and easy to drink spirit, with the lite bread taste. Some users found this interesting.
8kg unmalted wheat + 8 kg rye malt
Water - 52l
Mashing & fermentation
Mashing & fermentation are almost conventional for grain spirits.
1. Correct water pH. I always correct water for grain mashing to pH 5.5-5.6 using digital pH meter from Ali & concentrated sulfuric acid.2. Heat the water to about 50oC.
3. Add of milled unmalted wheat.
4. Heat the mixture to 63oC.
5. Add of small quantity of rye malt (about 0.8-1 kg) for preliminary starch conversion.
6. Heat the mixture to about 95oC. Cook wheat for 1-1.5 hours.
7. Cool the cooked wheat down to 63oC. Add rye malt.
8. Starch conversion at 63oC for 2 hours.
9. Cool the mash down to 34oC. Add 300g dried bread yeast.
10. Wait for 10-20 minutes for fermentation to start. I wait for the first signs of process.
11. Cool the wort down to 18-20 oC. During fermentation temperature rises to 32oC. If this happens - I cool down the wort.
12. Wait for the fermentation to end. It usually takes 48-55 hours.
You can use dried bread yeast or distiller's yeast - any type you have. Fermentation is quick with a huge amount of foam. I use triple dose of defoaming agent with rye, compared with barley malt, for fermentation +1 extra dose before 1st distillation.
It is necessary to distill wort as soon as possible – right after the fermentation ends. In case of bread wine we don’t need secondary bacterial fermentation. So, the process should be as quick as possible.
Distillation should be done as fast as possible using the simplest direct-flow condenser with NO parts (like dephlegmator or reflux condenser) that help strengthening distillate (raising the output ABV). I even provide the ascending part of vapor circuit with heat insulation. We should divide the result into two parts - Strong low wines & Weak low wines. Collect them into separate containers.
Why should we distill like this?
What wort consists of?
1. Water, for the most part, 80-90 percent of the volume.
2. Ethanol, dissolved in it, 8-12 percent (and sometimes more)
3. Remains of yeast
4. Remains of the original product, if we are talking about grain wort (grits or flour).
a. Heads. They fly out of the wort before alcohol in any case. During distillation, it is the heads that first come out, and they leave almost completely.
b. Tails. Heavy fractions (and, in fact, water). Their behavior during distillation is almost simple. Of course, they are significant for all malt/grain distillates, cause they carry a taste & aroma of raw material.
c. Transitional fractions. They seem to be like tails, but they can behave like heads. And at the same time, they are successfully masked even by the smell of ethanol. And they are very poisonous.
One of the worst transitional fractions is isoamyl alcohol (Iaa). The method described is developed to prevent it from getting into distillate or at least minimize its content in the final product. High Iaa content may corrupt distillate’s aroma and taste.
Isoamyl alcohol evaporation speed depends on the ethanol content in the liquid inside the distilling tank. The less the ethanol content the more isoamylol evaporates.
With 10% ethanol in a distilling tank, the Iaa evaporates about three times faster than ethanol. For the time that we extract 1% of the ethanol from the distilling tank, at the same time 3% of the isoamylol is released.
With 20% ethanol in a distilling tank, isoamylol evaporates twice as fast. That is, having got 1% of the alcohol present in the distilling tank, together with it we will take 2% of the available Iaa.
With 40% ethanol the coefficient becomes equal to one. For each percent of distilled ethanol we get 1% of distilled Iaa.
And with 60% ethanol in the still, the coefficient decreases to 0.2, that is, after distilling 1% of ethanol inside the still, we take only 0.2% of Iaa inside the still.
So, the main conclusion is:
If we have a 10% wort, at the moment when we distilled 50% of the ethanol from the still, together with it we distilled 99% of isoamylol and similar fractions.
When to change low wines receiver? There are 2 considerations:
It is easy to indicate significant Iaa content by smell. Just drip a few drops of distillate flowing from the condenser into the palm of your hand and rub. Then smell the result. The first ethanol evaporates (perhaps with the remnants of heads). AFTER the ethanol you’ll smell the solvent or nitro-paint - this is the smell of isoamylol. When the isoamylol evaporates, the smell of bread remains - these are the tails.
From practice – isoamylol ceases to be felt in the smell approximately between 93oC and 95oC on thermometer installed before condenser.
All the time we can smell Iaa – we collect Strong low wines (1st part of low wines with nearly all Iaa in it). After that (also looking at the temperature before the condenser) we change the low wines receiver and collect Weak low wines (2nd part of low wines with no Iaa in it) till we reach around 1-1,5% ABV distillate flowing out from the condenser.
Strong low wines distillation
The main goal on this step is to use distillation process with maximum separation that will surely lock the Iaa and similar fractions inside the still and won’t let them get into the product. I suppose that the best choice is using a 5-10 plates bubbling reflux column (or short packed reflux column). I have one. It makes 93-94% distillate (here we have a special term for it – subrectificate) under the automated control with temperature delta = 0,1-0,2 oC in the deph & flow controlled with valves. Under these conditions no noticeable quantity of Iaa can reach the final distillate. I dilute this part with water to about 30% ABV. Distillation should be done normally. First - heads are distilled, then – the potable distillate.
When I open the still to clean the equipment after this stage the Iaa smell (solvent or nitro paint) is usually so strong and awful that the only wish is to put on a gas mask or to run out of the room immediately.
I didn’t try other equipment configurations for Strong Low Wines distillation, but I’m quite sure that simple direct-flow condenser is not able to give a good result. Some configurations with reflux condensers can be useful. But if you use equipment with lower separation ability, it is better not to dilute Strong low wines before distillation.
What to do with derived distillate-subrectificate? There are 2 basic variants:
a) AFTER distilling the second part – Weak low wines, this subrectificate is added to final product.
b) Subrectificate is added to Weak low wines BEFORE distillation.
I prefer the second variant, because I think, that raising Weak low wines ABV before distillation to something between 25-29% is better than to distill from 19-20% ABV liquid.
Weak low wines distillation
For Weak low wines distillation you can choose any method & equipment you like. Even a simple pot-still distillation through direct-flow condenser will give a good result. But I prefer using the same bubbling reflux column.
First, I distill the heads second time, compressing them with reflux turned on and automatic flow control using valves. The volume of heads this time is relatively low – about 1/4 – 1/3 or less of heads volume from Strong low wines distillation.
After distilling heads I turn off reflux, get my output valves open and use column as a pot still with dephlegmator playing the role of condenser. According to my experience the lower (heart -> tails) cut should be done in the range 75%-70% ABV, measuring the current ABV of distillate flowing out of condenser.
Depending on the equipment and distilling parameters (heating power / distillation speed, separation quality of your equipment, distillation mode etc) you will get or won’t get tails valuable for next processing. If ethanol content of distilling liquid is high enough it may be useful to compress tails on the column with reflux turned on. The result can be added to the final product.
Final spirit, derived from several distillations will surely have relatively high ABV. It should be diluted to 38,5% ABV. This strength is traditional. You can also choose your own ABV value of the product.
1. I’m not the author of described distillation method. The author’s nickname on Russian home distillation forum is Gabriel 61 (profile). So, here in Russia method is widely known as “Gabriel’s distillation method”.
2. This method can surely be applied for any grain distillate. I suppose that only malt whisky is the exception.
3. Described method can be successfully used by home distillers. No ideas about perspectives of industrial application.