I’ve made quite a few fruit beers since I started brewing. Some of the beers have been unmitigated successes, other beers, well… But even when I was just starting, I didn’t mind playing around.
I’m kind of lucky compared to most brewers because I get fresh, home-grown fruit in season. I can throw in some fruit without worrying too much about wasting the fruit and, now that I’ve set up my new experimental brewing platform, I can add fruit, or anything else, to fermenting beer without worrying about wasting too much beer.
So here’s my advice for people wanting to add fruit to fermenting.
1. Freeze Your Fruit First (Usually)
Freezing breaks down cell walls which releases the flavour in to your beer. It also kills some organisms that might otherwise compete with yeast and create off-flavours. If you’re using a fruit that tastes different after having been frozen (try testing this if you don’t know), then just try crushing or blending the fruit before adding it. You’ll taste why.
2. Add the Fruit Between Primary and Secondary
Ferment your beer in the primary as normal. Then rack it to another primary fermenter and add your fruit. You will need the extra head-space because the sugar in the fruit will restart fermentation. After your fruit and beer have spent at least 2-3 weeks together, rack it to the secondary (if you can count this would be the tertiary, but I’m trying to keep the standard brewing paradigm from collapsing under the weight of cherries and raspberries).
Which brings me nicely to:
3. Screw Sanitation, Use Raw Fruit
The sanitation Nazis own the Internet.
If you have let the yeast do most of the work in your primary, you will be adding the fruit to an environment (alcoholic and hoppy) which prohibits the growth of most organisms. Add a healthy culture of highly-competitive yeast to the equation and the odds are in your favour that you will have some damn good beer.
4. Sanitize Your Fruit
It’s not as important as #3, but if you have fruit that tastes fine after a little cooking, then quickly drop the fruit into boiling water to kill any competing organisms. But it’s not a big deal.
5. Use Fresh, Locally Grown, In-Season Fruit
Fruit when it is in-season and locally grown is so much tastier than fruit from the grocery store. Get the best you can and brew something else in winter.
6. Every Fruit is Different
Some fruit are easy to transfer in to beer. I’ve done raspberry, cherry, and prune-plum beers, but I hear apricot, blackberry, and apple can also be pretty good.
Some fruit disappear in a beer. Thanks to the advice of others, I’ve avoided strawberry, peach, and blueberry.
Some fruit lose essential flavour elements in beer. Like red-currants.
7. Use an Plain Yeast
You might be able to find a yeast that complements whatever fruit you are using. But, when starting, use American Ale yeast and just enjoy the malt and fruit flavour without complicating things.
Specific Fruit Quantities
Specific fruit quantities depend on the base beer. For a 23 L (5.5 gal) batches, here is some limited advice based on my mistakes, er experience…
Raspberry: About 0.9 kgs (2 lbs) gives you a very distinct fruit flavour in a raspberry wheat beer.
Cherry: About 1.8 kgs (4 lbs) of half-sweet half-sour cherries produces a very balanced beer on a Nut-Brown base.
Prune-Plums: 0.9 kgs (2 lbs) in a Stout puts the fruit and malt flavours in conflict. Try 0.45 kgs (1 lbs) in a less full-flavoured beer.
Rhubarb: 0.45 kgs (1lb) in a Hefeweisen didn’t work well. To get rhubarb beer to work try a sweeter base beer and use less rhubarb.
Red-Currant: This falls under the “lose essential flavour element” category. I think it could be made tolerable mixed in the right beer, with other fruit, but why?
If you’ve tried any other fruit, please add your experience in the comments.