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Cultural Ferment

Tonto: Uganda’s Banana Beer, How It’s Made, and Why Ripe, Peeled Bananas Matter

By Updated 2 min read

Tonto is Uganda’s traditional fermented banana beer of the Baganda Kingdom — ripe bananas squeezed with roasted sorghum flour and fermented 24–72 hours. Learn its Buganda history, banana variety selection, and home recipe.

At a glance

Tonto is Uganda's traditional banana beer. Ripe beer bananas are peeled and squeezed with grass, and the juice is diluted, mixed with roasted sorghum and fermented by wild yeasts and bacteria, traditionally drunk at about 24 hours. Traditional batches reached about 2–5% alcohol. In a 2026 study, half the batches exceeded Uganda's methanol limit, linked to unripe or unpeeled bananas, so use ripe, fully peeled fruit.

  • Ugandan banana beer from ripened, peeled beer bananas and roasted sorghum.
  • Traditionally drunk at about 24 hours of fermentation.
  • Over 60 hours: pH 4.9 to about 3.6 and alcohol up to about 4.7% v/v.
  • Half of 42 traditional batches exceeded Uganda's 60 mg/L methanol limit.
  • High methanol was linked to unripe or unpeeled bananas.

Ferment profile

Origin
Uganda
Fermentation
Mixed (lactic + alcoholic)
Main microbes
Wild yeasts (including Saccharomyces cerevisiae) and lactic acid bacteria
Live cultures
Yes
Alcohol
Moderate (2–6%)

Tonto – also called mwenge bigere or orubisi – is Uganda’s traditional banana beer, brewed for weddings, funerals, rites of passage and the birth of a child. It’s made from the juice of special beer bananas, fermented briefly with coarsely ground roasted sorghum into a cloudy, fruity, lightly sour drink. Its East African relatives include Rwanda’s urwagwa and the Chagga mbege of Kilimanjaro, which is brewed with malted millet (Shayo et al., 1998).

How Tonto Is Made

A 2026 study from Makerere University followed traditional tonto production in Ntungamo and Kalungu districts (Atwine et al., 2026):

  1. Beer bananas – cultivars such as Kayinja (Pisang Awak), Kisubi and Mbidde – are ripened for 3–8 days in a pit lined with banana leaves.
  2. The ripe bananas are peeled, mixed with spear grass (Imperata cylindrica) and squeezed by foot in a canoe-shaped wooden vat; the grass acts as a pressing and filtering aid.
  3. The juice is diluted with water and mixed with coarsely ground roasted sorghum.
  4. It ferments spontaneously in covered wooden vats, where temperatures can reach 40°C, and is filtered again before drinking. The 24-hour stage is the traditional point for drinking.

What Happens in the Pot

Wild yeasts and lactic acid bacteria from the bananas, the vat and the sorghum do the work. Over 60 hours in the Makerere study, pH fell from 4.9 to about 3.6, sugars (as °Brix) from 15 to 5, and alcohol rose to an average of about 4.7% by volume. Esters gave the best batches their fruity, banana aroma, and those were the ones tasters liked most (Atwine et al., 2026). An earlier study of traditional tonto measured about 2% alcohol and found it stayed acceptable for about 4–5 days of storage (Gensi et al., 2000).

The Methanol Problem

The same study found a serious safety gap. Methanol in the 42 batches ranged from none to 950 mg/L, and half of them exceeded Uganda’s limit of 60 mg/L. The high values all came from one district, where processors reported using unripe or unpeeled bananas; samples from the other district stayed between 0 and 44 mg/L. The authors explain that methanol forms when microbes break down the fruit’s pectin. The authors also warned of the added risk when tonto is distilled into spirits (Atwine et al., 2026). For a home brewer the lessons are simple: use only fully ripe fruit, peel every banana, drink it young, and never distil it.

Making It at Home

Ugandan beer bananas are hard to find elsewhere. Very ripe, fully peeled dessert bananas make a fair stand-in, though the flavour will differ. Published studies don’t give a standard ratio of water and sorghum, so the recipe card’s 50 g of roasted sorghum per litre is our starting point, not a traditional measure. Drink tonto within a day or two, as Ugandan drinkers do. Like palm wine, it changes by the hour and isn’t meant to be kept.

Recipe: Home-Brewed Tonto

Makes
About 2 litres
Hands-on
45 min
Fermentation
Bananas ripened 3–8 days; fermentation about 24–48 hours
Temperature
Warm room temperature, about 25–30°C
Difficulty
Moderate

Equipment

  • Large bowl
  • Fine cloth or nut-milk bag for pressing
  • Heavy dry frying pan
  • 3-litre jar or crock with a cloth cover

Ingredients

  • 2 kg very ripe bananas (beer bananas if available; peeled completely, no green fruit)
  • About 1 litre water (boiled and cooled)
  • 50 g per litre of diluted juice (about 100 g) whole sorghum grain, roasted and coarsely ground (our starting amount)

Method

  1. Ripen the bananas until the skins are fully yellow with brown spots. Discard any that are green, mouldy or fermented-smelling.
  2. Peel every banana completely and mash the flesh by hand in a large bowl.
  3. Press the mash through a fine cloth to collect the juice, adding a little of the water to help it release. Discard the pulp.
  4. Dilute the juice with water to about 2 litres in total.
  5. Roast the sorghum in a dry pan until fragrant and lightly browned, grind it coarsely, and stir it into the juice.
  6. Pour into the jar, cover with a cloth and leave in a warm place for about 24 hours, until it's bubbling and gently sour; taste again at 48 hours if you like it stronger.
  7. Strain and drink within a day or two, kept covered and cool. Never seal it in a closed bottle, and never distil it.

Frequently asked questions

What is tonto?

Uganda's traditional banana beer, made from the juice of ripened beer bananas fermented with roasted sorghum, and drunk young.

How strong is tonto?

Studies of traditional tonto measured about 2% alcohol in one survey and up to about 4.7% after 60 hours in another, depending on the batch and how long it ferments.

Why is sorghum added to tonto?

Coarsely ground roasted sorghum is traditionally mixed into the diluted juice before fermentation; it adds body and a toasted flavour.

Is homemade banana beer dangerous?

It can contain methanol. In a 2026 study, half of traditional tonto batches exceeded Uganda's methanol limit, linked to unripe or unpeeled bananas. Use ripe, fully peeled fruit and never distil it.

How long does tonto keep?

It's traditionally drunk at about a day old; one study found it acceptable for about 4–5 days, getting more sour as it goes.

What's the difference between tonto and mbege?

Both are East African banana beers, but mbege, from the Chagga of Kilimanjaro, is brewed with malted millet.

Sources

  1. Atwine A et al. (2026). Characterization of physicochemical properties, volatile compounds, and sensory attributes of Tonto, a traditional Ugandan banana-based alcoholic beverage. Food Sci Nutr 14(7):e72071. Link
  2. Gensi RM, Kyamuhangire W, Carasco JF (2000). Traditional production method and storage characteristics for banana beer (tonto) in Uganda. Acta Hortic 540:569–574. Link
  3. Shayo NB et al. (1998). Assessment of cyanogenic glucoside (cyanide) residues in Mbege: an opaque traditional Tanzanian beer. Int J Food Sci Nutr 49(5):333–338. Link
#East and Southern Africa
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