Brewing with tropical fruit: mango, passion fruit and pineapple

Choose the fruit and the form

Ripe fruit has the most flavour. Frozen fruit is good because freezing breaks the cell walls and releases juice. Canned or pasteurised purée is the safest, since it is already sanitary. Fresh fruit can carry wild yeast and bacteria, so wash it, remove the skin where bitter and freeze it for a day before use. Do not use fruit that is mouldy or fermenting on its own.

When to add it

Heat drives off fruit aroma, so adding fruit to the boil loses most of what you want. The usual route is to add fruit to the fermenter after the main fermentation has slowed, for a secondary ferment of one to two weeks. Alternatively, add it at the end of the boil, in a whirlpool at about 75 °C for 15 minutes, which pasteurises it while keeping some aroma. Fruit added to the fermenter restarts fermentation, so wait until it settles again before bottling.

How much

A mild fruit character needs around 100 g of fruit per litre of beer. A strong one needs 200 to 250 g per litre. Start low. You can add more in the next batch, but you cannot take it out of this one. Passion fruit is the exception, with intense acid and aroma: 50 to 100 g of pulp per litre can be plenty.

The three fruits

Mango. Sweet, creamy, soft. Pairs with a hazy pale ale or wheat beer. It adds pectin and haze, so a pectic enzyme added with the fruit helps clarity.

Passion fruit. Sharp, floral and fragrant. Its acid brightens a beer and it works well in a pale beer or a light sour. Strain the pulp if you want a clearer beer.

Pineapple. Fresh pineapple contains bromelain, an enzyme that breaks down protein, which can hurt head retention in the beer. Use canned or cooked pineapple, where heat has deactivated the enzyme. Freezing does not.

Sugar, restarts and safe bottling

Fruit sugar is fully fermentable. Adding fruit adds alcohol and it adds CO2. If you bottle before the fruit has finished fermenting, the bottles will carry far more pressure than planned. Wait until the gravity is stable for several days, then bottle and use the standard priming rate. Read bottle conditioning in hot weather and consider PET bottles for your first fruit batches.

Heat, hygiene and storage

Fruit in a warm room ferments fast and can foam over. Leave plenty of headspace and use a blow-off tube. Keep temperatures in check, as in homebrewing in a hot climate. Sanitise every utensil that touches the fruit and keep fruit flies away from open containers, as discussed in homebrewing in the humid tropics.

Fruit beers fade faster than plain ones, since the fresh aroma is delicate. Chill the bottles and drink within a couple of months. Keep them upright and cold, away from light.

Sourcing and preparing the fruit

Buy fruit at its peak and plan the brew around the season. Mango is at its best for a few weeks in many places, so freeze purée in 500 g bags for the rest of the year. Wash the fruit with clean water, peel it and cut the flesh from the stone. Pulp the flesh in a blender without any seeds. Weigh the pulp for the recipe.

Frozen pulp is easy to dose: take out one or two bags, thaw them in a sanitised container and add the lot. Record how much you used per litre. Next batch, you can move the figure up or down, which is how you tune a fruit beer to your taste.

If you want more aroma, add a second, smaller dose of fruit at the end of conditioning. It lifts the fresh fruit smell, but check the pressure risk again, because new sugar may restart the yeast.

Balance and tasting

Fruit should support the beer, not bury it. A light, low-bitterness base, such as a wheat beer or a pale ale with a soft hop profile, gives fruit room. Keep bitterness modest, around 15 to 25 IBU, because high bitterness fights fruit acid. Taste before you bottle. If the fruit is too faint, add more to the fermenter and wait for the gravity to settle again before bottling.

Making fruit beer work every time takes some understanding of sugar and fermentation, which we teach in class.

Common questions

When should I add fruit to beer?

After the main fermentation has slowed, in the fermenter, for one to two weeks. Or in a whirlpool near 75 °C if you want to pasteurise it.

How much mango should I use?

About 100 to 250 g per litre depending on how strong you want it. Start at the low end.

Why did my fruit beer start fermenting again?

Fruit sugar is fermentable. The yeast restarts when it meets new sugar. Wait until the gravity is stable before you bottle.

Can I use fresh pineapple?

It can hurt foam because of bromelain. Canned or cooked pineapple is safer, because heat deactivates the enzyme.