Sugar Sources

Part of Alcohol and Distillation

Sources of fermentable sugars — what yeast can and cannot eat, and where to find it.

Why This Matters

Yeast converts sugar into alcohol. No sugar, no alcohol — it is that simple. But “sugar” to a yeast cell means something very specific: simple sugars (monosaccharides and disaccharides) that yeast enzymes can process. Table sugar (sucrose), fruit sugar (fructose), grape sugar (glucose), and malt sugar (maltose) all work. Starch does not — it must be converted to sugar first through malting or other enzymatic processes.

In a rebuilding scenario, refined white sugar will be among the first commodities to disappear. You need to know every possible source of fermentable sugar in your environment, how to extract it, and how to convert complex carbohydrates into simple sugars that yeast can use. This knowledge determines whether you can produce alcohol for antiseptic, solvent, fuel, and preservation — not just for drinking.

The diversity of your sugar sources also determines the diversity of your products. Honey makes mead. Fruit juice makes wine. Grain starch (malted) makes beer and whisky. Sugarcane or beet juice makes rum. Each sugar source produces a distinctly different product with different uses.

Direct Sugar Sources

These contain sugars that yeast can ferment immediately without additional processing.

Honey

The oldest and most reliable fermentable sugar source. Honey is approximately 80% sugars (fructose and glucose primarily), with the remainder being water and trace compounds. Diluted to 15-25% sugar concentration, honey ferments readily into mead.

Yield: 1 kg of honey produces approximately 350-400 ml of pure alcohol (ethanol).

Advantages: Available nearly worldwide where flowering plants grow. Stores indefinitely without refrigeration. Already sterile due to low water activity. Contains some wild yeast and nutrients that aid fermentation.

Processing: Simply dissolve honey in warm water (not boiling — heat destroys subtle flavors and can set proteins that cause haze). A ratio of 1 part honey to 4 parts water produces a light mead; 1:3 produces a stronger one.

Fruit

Any sweet fruit contains fermentable sugars — primarily fructose and glucose.

Fruit	Sugar Content	Fermentation Notes
Grapes	15-25%	Premier wine fruit; balanced acid
Apples	10-15%	Makes cider; needs no water addition
Pears	10-16%	Makes perry; ferments slowly
Plums	8-12%	Good for brandy; high pectin
Berries (various)	5-10%	Low sugar; often need supplementation
Dates	60-70% (dried)	Excellent sugar density
Figs	50-65% (dried)	Traditional in Middle East
Bananas	12-15%	High starch when green; sugar when ripe

Processing: Crush or press fruit to extract juice. Fermenting whole crushed fruit (must) also works — the skins add tannin and flavor. For dried fruits, chop and soak in warm water for 24 hours to dissolve sugars.

Wild Fruit

Do not overlook wild fruits: crabapples, elderberries, blackberries, rosehips, hawthorn berries, and wild grapes all contain fermentable sugars. They may need sugar supplementation (from honey or another source) to reach adequate concentration for a good fermentation.

Tree Sap

Several tree species produce sap rich in sugar:

• Sugar maple (Acer saccharum): 2-3% sugar. Requires 40 liters of sap to produce 1 liter of syrup. Can be fermented directly (low alcohol) or concentrated first.
• Birch: 0.5-2% sugar. Very dilute but available in enormous quantities in northern forests.
• Palm trees: Various species produce sap with 10-15% sugar content. Toddy palm, coconut palm, and date palm are traditionally tapped for fermentation.
• Agave: The heart (piña) contains starch and inulin that convert to fermentable sugars when roasted. This is the basis of tequila and mezcal production.

Collection: Drill a small hole (1 cm diameter, 5 cm deep) into the trunk in late winter/early spring. Insert a spout (hollow tube) and hang a collection vessel. One tree can yield 40-80 liters of sap per season without harm.

Sugarcane and Sugar Beets

If you can grow these crops, they are the most productive sugar sources:

• Sugarcane: Tropical/subtropical grass with 12-18% sugar content in the stalk juice. Crush stalks to extract juice, ferment directly. One hectare of sugarcane can produce 5,000-8,000 liters of juice.
• Sugar beet: Temperate root crop with 15-20% sugar content. Slice or shred roots, soak in hot water (70-80°C) to extract sugar, ferment the resulting liquid.

Starch Sources (Require Conversion)

Starch is a chain of glucose molecules linked together. Yeast cannot break these chains — you must convert starch to sugar before fermentation. This process is called saccharification.

Grains

Grain is the most important starch source for alcohol production. Wheat, barley, corn (maize), rice, rye, oats, millet, and sorghum all contain 60-75% starch by weight.

The malting process converts grain starch to sugar using the grain’s own enzymes:

1. Steep: Soak grain in water for 12-24 hours (drain and re-soak every 8 hours)
2. Germinate: Spread soaked grain on a clean surface, 5-10 cm deep. Keep moist and turn daily. Wait until rootlets are 1-2 cm long (3-5 days for barley)
3. Kiln: Stop germination by drying the grain with gentle heat (50-70°C). This preserves the enzymes while halting growth
4. Crush: Grind the malted grain coarsely (not to flour — a rough crush is better)
5. Mash: Mix crushed malt with warm water (62-68°C) and hold for 1-2 hours. The amylase enzymes convert starch to maltose and glucose

Barley is the preferred grain for malting because it produces the highest levels of amylase enzymes. However, you only need about 20-30% malted barley — the rest can be unmalted corn, wheat, rice, or any other starchy grain. The barley enzymes will convert all the starch present.

Yield: 1 kg of grain produces approximately 350-400 ml of pure ethanol.

Root Vegetables

Potatoes, sweet potatoes, cassava (manioc), yams, and taro are all starch-rich and can be converted to fermentable sugar.

Conversion methods:

1. Cooking: Boil or steam the roots until soft. This gelatinizes the starch, making it accessible to enzymes. Then add crushed malted barley (10-20% of the total weight) at 62-68°C and hold for 1-2 hours.

2. Koji (Asian method): Inoculate cooked grain or roots with Aspergillus oryzae mold (koji). The mold produces amylase enzymes that convert starch to sugar over 2-3 days. This is the traditional method for sake (rice wine) and shochu.

3. Acid hydrolysis: Boil starchy material with dilute acid (sulfuric, hydrochloric, or even strong vinegar) for several hours. The acid breaks starch chains into glucose. Neutralize the acid with ash or limestone before fermentation.

Root Crop	Starch Content	Yield (ethanol/kg)
Potato	15-20%	100-120 ml
Sweet potato	20-25%	120-150 ml
Cassava	25-35%	150-200 ml
Yam	20-30%	120-170 ml

Other Starch Sources

• Chestnuts: 40-50% starch. Roast, grind, mash with malt enzymes.
• Acorns: 40-55% starch. Must be leached first to remove bitter tannins (soak in running water for days), then process like grain.
• Cattail roots (Typha): 30-40% starch. Abundant in wetlands. Dry, grind, and mash with malt.
• Bread and baked goods: Already gelatinized starch. Soak in water with malt to convert remaining starch.

Preparing a Fermentable Wash

Regardless of your sugar source, the goal is to create a liquid with:

• 10-20% sugar concentration (measured by taste — noticeably sweet but not syrupy)
• Adequate nutrients for yeast (fruit juice provides these naturally; grain mashes need nothing extra; pure sugar solutions benefit from adding a handful of crushed grain or a tablespoon of yeast nutrient)
• pH between 4.0 and 5.5 (slightly acidic — add lemon juice or vinegar if the wash is too alkaline)
• Temperature between 18-30°C when yeast is added

Sugar Concentration Guide

Desired Alcohol	Sugar Needed	Taste Reference
5-7% (beer)	10-12%	Lightly sweet, like apple juice
10-14% (wine)	18-25%	Clearly sweet, like grape juice
15-18% (strong wine)	28-32%	Very sweet, almost syrupy

Too Much Sugar

If the sugar concentration exceeds 25-30%, most yeast strains will struggle or die from osmotic pressure. The high sugar concentration draws water out of the yeast cells, dehydrating them. Start with a moderate concentration and add more sugar partway through fermentation if you want higher alcohol content.

Maximizing Your Sugar Extraction

From Fruit

• Freeze and thaw fruit before pressing — ice crystals rupture cell walls, releasing more juice
• Add pectic enzyme (naturally present in the fruit’s own pulp if left to sit for 24 hours) to break down pectin and free trapped juice
• Press fruit in a cloth bag, twisting to extract maximum juice

From Starchy Sources

• Finely grind or grate the material to maximize surface area
• Cook thoroughly before adding malt enzymes — raw starch is largely inaccessible
• Hold the mash at 62-68°C for a full 90 minutes — rushing this step leaves unconverted starch that wastes potential alcohol

From Dilute Sources (Sap, Dilute Juice)

• Boil to concentrate before fermentation — reducing 40 liters of maple sap to 10 liters gives a much more efficient fermentation
• Alternatively, freeze and remove ice — sugar stays in the liquid while water freezes out (freeze concentration). This requires no fuel.