Adding coffee to beer

Which beer to put it in

Coffee is happiest in dark beers, where it adds to what is already there. A stout or porter is the classic home. Our guide to brewing a stout at home gives a good base recipe.

Pale coffee beers exist too, often made with lightly roasted beans for fruit and floral notes. They are harder to get right, because nothing hides an off note. Start dark.

Coffee adds bitterness of its own. If you plan to add coffee, bring your hop bitterness down by a third or so, otherwise the finished beer can feel harsh.

Why not in the boil

Hot extraction is how we make coffee for drinking, so the kettle seems obvious. In practice boiling or near-boiling wort pulls out a lot of harsh bitterness and drives off the volatile aroma you wanted. The beer tastes like coffee left on a hot plate.

Add coffee cold, late in the process, when the fermentation has finished. Adding it before or during fermentation also loses aroma, because the CO2 bubbling out of the beer carries the volatile coffee notes away with it.

The one exception is a small amount of finely ground coffee added at flame-out in a very roasty stout, where some brewers like the deeper, darker note. Treat that as an experiment for later, not a starting point.

Method one: cold brew

This is the method we recommend for a first try, because it gives you the most control.

1. Make a strong cold brew: coarsely ground coffee steeped in cold water in the fridge for 12 to 24 hours, then filtered. Use boiled and cooled water to keep it clean.
2. When the beer is finished, pour a measured glass of it and add cold brew a little at a time with a syringe or measuring spoon until it tastes right.
3. Scale that ratio to the whole batch and add it at bottling or kegging.

That bench test is the step people skip and the one that matters most. It turns a guess into a measured dose. The cold brew also dilutes the beer slightly, so account for that in strong beers.

Method two: whole beans in the fermenter

Some brewers prefer to add whole or coarsely cracked beans straight to the finished beer, sometimes called dry beaning. The aroma is often more intense and fresh.

A common starting point is around 3 to 5 g of beans per litre for about 24 hours. Taste every 12 hours and pull them out when you like it. Left too long, beans give a grassy, vegetal note. Put them in a sanitised mesh bag so you can lift them out cleanly. Dry roasted beans carry little risk of infection, but sanitise the bag and anything else that touches the beer.

Choosing beans

India grows excellent coffee, which makes this one of the easier experiments to source locally. Arabica from Chikmagalur, Coorg or the Nilgiris gives cleaner, sweeter coffee character. Robusta is more bitter and earthy, which can work in a big stout in small amounts. Monsooned Malabar, with its low acidity and earthy, spicy profile, suits a dark beer well.

If you can, buy from a small roaster who will tell you the estate, the processing and the roast date. Washed coffees taste cleaner and brighter. Natural (dry-processed) coffees bring more fruit, which can be lovely in a porter.

Buy freshly roasted beans and grind just before use. A medium roast is a safe start. Very dark roasts add more bitterness than flavour. The beer already has roast of its own.

Keep it fresh

Coffee aroma fades faster than most beer aromas. Oxygen and warm storage make it go stale, then papery. Add it at the end, package it with as little air as possible and keep it cold. Plan to drink a coffee beer within a couple of months.

Keep notes on the beans, dose and contact time each time. The same approach works for other additions; our guide to adding fruit to beer follows the same logic of adding late and measuring.

Small additions like these are where a solid grasp of fermentation and oxygen control shows. A guide can give you a dose. Knowing why a batch went stale is the harder skill.