I recently brewed a pale wheat beer as the base to show off the tart cherry plums that previously just made a mess of my back patio. This was the second year that I made it and was able to fine tune vs. last year's laissez-faire approach of just throwing them into a Galaxy Pale Ale that had no warning of its future.
Last year's rendition was full of plum flavor but did suffer from too much bitterness and a subtle tannic astringency from the plum skins. I'll share what worked, what didn't and how I've improved my process with respect to this beer.
It's not that I tried to make a beer in this style. Rather, I was inspired by these little cherry looking plums and knew they had to go into a beer. I had several fruit beers in play for submission to the California State Homebrew Competition and finding yet another category option worked in my favor.
For some background, what the heck is a Catharina Sour? According to the article in BYO, Gordon Strong says reported that it's "... a standard-strength wheat ale that had been kettle soured and had fresh tropical fruit added". Based on my read of the BJCP style description I felt that this year's batch of plum ale was indeed a match but not without some concern given I've never been to Brazil nor have I ever tasted a Catharina Sour.
Here are the key process steps in making a good Catharina Sour:
- Ensure mash pH is in the neighborhood of 5.1 to ensure a bright beer that isn't heavy or chewy.
- Back off on the crystal malts as they are not necessary and seem to compete with the fresh fruit.
- Beware of oxygen. Just like fresh fruit turns brown and funky (and not in a good way) in the presence of oxygen, your Catharina Sour will go South on you quickly unless you take care to minimize exposure at every step in the process (except at pre-pitch of your yeast).
- Make sure the fruit is very ripe.
- Reduce or even eliminate your hop bittering addition as this is where you may run into trouble. Bitter and sour is not a good combination. Also, keep your overall bitterness from hops in check. Whirlpool hops at say 180 degrees or less works great. You can derive plenty of hops to ensure it's beer and not a carbonated fruit drink.
- Use a neutral-ish yeast and good temperature control to keep esters from fermentation in check. The aroma from the fruit can be subtle and you wouldn't want a strong Belgian profile to hide your hard work.
- Don't skimp on the fruit. For this year's brew I picked 18lbs of de-stemmed cherry plums including pits for 10 gallons. I generally target at least 2lbs of fruit for every gallon of beer.
- Blending fruits can really help. I decided to add 3lbs of peaches to this beer after I tasted the plum only brew. I just knew it could be better and the combination of cherry plums and peaches gave it some complexity.
- Fresh fruit is awesome. However, it can lead to a beer that is too clean and akin to a nice glass of Rosè wine. I've found that reducing fruit for several hours over low heat is a great way to bring out the most in these fruits. You can also determine your ratio of fresh to stewed based on how ripe the fruit is and what type of fruit.
More to come. This post is in progress...