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Alcoholic drinks from Europe

Potato beer (potato mash ferment)

Potato "beer" is the fermented potato mash that distillers turn into potato spirit. Cooked potatoes are mashed, their starch is turned into sugar by enzymes, and distillery yeast ferments the sweet mash for about three days. A 2025 lab study of Polish potato spirit gives the times and temperatures used here.

Fully documentedAlcoholic drinks2.6 days – 2.9 days

Recipe

Amounts from a sourceLab-scale method from a 2025 study, with 3 L of sweet mash in each fermentation flask.
Potatoes, washedThe study's potatoes held 16.80 % dry matter and 8.61 % starch[balcerek2025]
α-amylase enzyme preparation (liquefaction)0.50 mL per kg of starch[balcerek2025]
Glucoamylase enzyme preparation (saccharification)0.72 mL per kg of starch[balcerek2025]
Ammonium hydrogen phosphate (yeast nutrient)0.3 g per litre of mash[balcerek2025]
Dry distillery yeast (Saccharomyces cerevisiae)0.3 g per litre of mash[balcerek2025]
Starterdefined-culture: dry distillery yeast

Total time across the recorded steps: 2.6 days – 2.9 days

Start
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120–152 °C

What changes: Steam under pressure cooks the potatoes and bursts the starch out of their cells

Step 1 of 5
Steam the potatoes under pressure
Time
40 min
Reported
Temperature
120–152 °C
Reported
Salt
None given
Acidity
Not documented
Which microbes the steps name, step by step
Saccharomyces cerevisiae
Yeasts

The study also tested a pressureless method that crushes raw potatoes and heats them in water to 90 °C. Output: cooked potato pulp, sterilised.

Flavour
Not documented
Texture
Not documented
Colour
Not documented

Microbes at work in this step

Not documented for this step.

Method

Measured measured in a studySet fixed by a specification or tested recipeReported one source reports itTypical a general value, not sourced for this fermentUnconfirmed not yet checked against a source

At a glance

Potato "beer" is the fermented potato mash that distillers turn into potato spirit. Cooked potatoes are mashed, their starch is turned into sugar by enzymes, and distillery yeast ferments the sweet mash for about three days. A 2025 lab study of Polish potato spirit gives the times and temperatures used here. Made in 5 steps over 2.6 days – 2.9 days. The longest step, ferment the sweet mash with distillery yeast, takes 2.6–2.9 days (Balcerek M 2025) and runs at 31–33 °C (Balcerek M 2025). Saccharomyces cerevisiae distillery strains does most of the fermenting.

Key numbers
Main step2.6–2.9 daysMeasured[balcerek2025]Ferment the sweet mash with distillery yeast
Temperature31–33 °CReported[balcerek2025]Ferment the sweet mash with distillery yeast
AciditypH 4.8–6Measured[balcerek2025]Turn the starch into sugar with glucoamylase

What makes this one different

Potatoes hold starch, not sugar, so the mash needs a starch-splitting step (enzymes in the study) before yeast can ferment it. Unlike beer, the wash is made to be distilled. In the study, pressure steaming, one of two methods tried, cooked and sterilised the tubers.

Related ferments

Safety

Potato distillates can be high in methanol, a poison that can blind and kill. The 2025 study gives the limit for potato spirit as 1000 g per hL of pure alcohol, citing EU Regulation 2024/1143; its distillates held 699.99 to 1530.95 mg per litre of pure alcohol (about 70 to 153 g per hL), below that figure, and pressure-steamed mashes gave the most. A review of EU rules gives much lower limits for vodka (10 g per hL) and for ethyl alcohol of agricultural origin (30 g per hL), and all these distillates were above both. These are lab results and do not clear a home distillate.

History and sources

Every number is labelled with how it is known. How this atlas is made

In Sweden, a 1914 handbook of Swedish history and statistics says potatoes were found usable for distilling in the middle of the 18th century, soon after the potato arrived, but general use for spirit probably began only at the start of the 19th century. It gives 17 % of the 1872 potato crop and 7.6 % of the 1912 crop going to the distilleries.

  1. [balcerek2025] Balcerek M., Mielczarek R., Dziekońska U., Pielech-Przybylska K., Patelski A. 2025, The impact of production technology on the quality of potato spirit, Molecules 30(22):4330paper
  2. [blumenthal2021] Blumenthal P., Steger M.C., Einfalt D. et al. 2021, Methanol mitigation during manufacturing of fruit spirits with special consideration of novel coffee cherry spirits, Molecules 26(9):2585 (EU methanol limits, general safety text only)paper
  3. [rostrup2016] Rostrup M., Edwards J.K., Abukalish M. et al. 2016, The methanol poisoning outbreaks in Libya 2013 and Kenya 2014, PLoS ONE 11(3):e0152676 (outcomes of poisoning, general safety text only)paper
  4. [guinchard1914] Guinchard J. (ed.) 1914, Sweden, historical and statistical handbook, second part (industries), p. 346 (spirit manufacture), Project Runebergbook
  5. [s1] Wikipedia (en), List of alcoholic drinks, entry for potato beer beside the potato spirits (outline only)wiki