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?
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.
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.
