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I have read a couple of recipes and descriptions of what needs to be done in order to produce alcoholic beverages such as vodka and rum. I was surprised to learn that basically all the sources use boiled potatoes, not raw, peeled potatoes mashed in a blender.

I think that the act of boiling is ruining the organoleptic properties of the potato and lowering the quality of the finished product. Why are you suppose to boil the potatoes?

Didgeridrew
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user2485710
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  • I'm a little confused about the premise here - we don't eat potatoes raw anyway, so what properties would you be ruining by boiling them? – Cascabel Nov 30 '14 at 03:02
  • @Jefromi I also don't eat potato + yeast, and when making alcohol you should let the yeast do its job . – user2485710 Nov 30 '14 at 03:03
  • Does the yeast care about organoleptic properties? I don't think it has human senses... – Cascabel Nov 30 '14 at 03:05
  • @Jefromi yes but why ? Why using power, water and time to do just that ? – user2485710 Nov 30 '14 at 03:06
  • Yup, I understand the question, I think it's a great question, I'm just not sure what human perceptions of smell/taste have to do with it, or why boiling ruins them. (It improves them - raw potatoes are inedible!) But it's not a big deal, the core question's fine. – Cascabel Nov 30 '14 at 03:14

2 Answers2

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Vodka by definition is a flavorless distilled alcohol, retaining any of the organoleptic properties of the grain or potato could be considered as ruining the end product.

Potatoes are a good source of starch, but brewers yeast has a limited ability to break down starch into usable fuel; its preferred fuel sources are relatively simple sugars like mono and disaccharides. In order to efficiently convert the starch in potatoes to sugar the potatoes must first be boiled so that the starches gelate. Once gelated, the potatoes are then Mashed-in with malted barley or wheat at a temperature around 150˚F so that the diastatic enzymes can break those starches into the sugars that yeast likes to eat. These same steps are used when making vodka from non-malted grains such as corn (maize).

Boiling the potatoes also helps reduce the number of surface microbes that could end up influencing the final product. Bacteria and wild yeast strains can lead to moldy, grassy, sour, and other unpleasant flavors that may necessitate multiple distillations to remove.

Making a mash of raw, peeled potato would likely yield something closer to a sourdough starter with a mix a naturally occurring yeasts and bacteria producing a small amount of alcohol along with acetic and lactic acids, as well as other compounds.

Didgeridrew
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  • thanks, great answer, but what about if I have some molasses instead of cereals ? The molasses is still being mixed with the mashed potatoes in the same way ? – user2485710 Nov 30 '14 at 20:46
  • Molasses can be used as a sugar source instead of potatoes, corn, or malted grains; but it should not be used as a replacement for malted grains used during the Mashing-in process. The process used to make molasses uses heat well above that which destroys the enzymes necessary to break down the potato starches during Mashing-in. – Didgeridrew Dec 01 '14 at 00:40
  • which implies that Molasses is often used as a single ingredients without cereals or potatoes ? – user2485710 Dec 01 '14 at 02:26
  • Correct. Since molasses, as well as sugar and malt syrup, are already simple sugars they can be used without needing the enzymatic Mashing-in step. You would just add together the molasses, yeast, and water and allow the yeast to do its job producing alcohol. – Didgeridrew Dec 01 '14 at 02:33
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    If you use molasses, by the way, you're producing rum. – logophobe Dec 01 '14 at 15:32
  • @logophobe My understanding is that rum can be made from either molasses, sugar, or sugar cane juice but, technically, has to be aged in oak barrels to classify as rum. There are also significant differences in the distillation processes used for rum and vodka. – Didgeridrew Dec 01 '14 at 20:37
  • @Didgeridrew Somewhat true, although if you use sugar cane or its juice, you're making a fairly different style of rum (known variously as aguardente, rhum agricole, or cachaca). It usually gets aged in oak and then filtered, sometimes all the way back to a white distillate, but some styles are aged strictly in stainless steel. – logophobe Dec 02 '14 at 03:03
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The raw starch in the potatoes has first to be gelatinized by boiling ,to expose the starch grains to the action of the Amylases (literally means enzyme that breaks down complex starch molecules into glucose). The yeast cannot digest the starch directly.The glucose so produced is broken down to ethanol(alcohol) and carbon dioxide. This is the same process used in brewing. The malted grain is the sources of Alpha and Beta Amylase as well as countless other enzymes.Commercially available enzymes could replace the malted grains , but these tend to be expensive and not always readily available in home use quantities. WARNING Don't forget that alcohol production is strictly controlled in most countries and is a criminal offence if produced without a licence. Distilling alcohol can be dangerous as alcohol fumes can be explosive.

Marcel
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