The Southern California Homebrewing Festival is coming up! As usual, I can’t make it due to a work event, but I am sending a keg with the Horse Thieves. The “bragging rights” competition this year is tiki-/island-themed beer, so anything that it is tropical/tiki is fair game. Charles, one of our club members and owner of Pacific Brewing Supplies, used an open source machine learning build (“AI”) to analyze a whole ton of recipes and come up with some ideas for our club. One of them was a Catharina Sour, which intrigued me enough to brew it!

Part of the appeal for me was that this is a style I’ve never made previously. Originating in Brazil, the BJCP describes it as “a refreshing fruited sour wheat beer with a vibrant fruit character and a clean lactic acidity.” It is essentially a bright, highly fruited Berliner weisse.

The recipe from Charles was pretty straight-forward, and I made only the most minimal modifications for my equipment and ingredient availability. I kettle soured with Lallemand’s Wildbrew Sour Pitch, and used US-05 (with its famous peachy notes) to provide a subtle fruitiness to enhance the tropical fruit. I chose Amoretti Craft Puree for the base fruit additions, having had good success with it in some batches a few years back. At the suggestion of the recipe, I also used the TrueFruit product (essentially granulated fruit concentrate) to brighten things up in the keg.

Catharina Sour

• 5 lb. Synergy Select Pilsen Malt (Briess)
• 4 lb. white wheat malt
• 0.5 tsp. BrewTanB, added to mash
• 1 pkg. Wildbrew Sour Pitch (Lallemand), for kettle souring
• 1.1 oz. Hallertauer whole hops (3.0% estimated alpha), from South Dakota
• 0.5 tsp. BrewTanB, 10 minute boil
• 0.5 tsp. WLN1000 yeast nutrient (White Labs)
• 1 pkg. US-05 Safale American ale yeast (Fermentis)
• 8 oz. (by weight) mango Amoretti Craft Puree, added to primary
• 8 oz. (by weight) passionfruit Amoretti Craft Puree, added to primary
• 1 oz. (by weight) TrueFruit passionfruit, added to keg
• 0.67 oz. (by weight) TrueFruit mango, added to keg
• 0.67 oz. (by weight) TrueLime, added to keg

Target Parameters

• 60 minute infusion mash, 152°, full volume mash
• 1.044 o.g., 1.009 f.g., 4.5% abv, 4 IBU, 3 SRM
• Blend of neutralized tap water and RO water to hit 86 ppm Ca, 5 ppm Mg, 64 pm Na, 36 ppn SO4, 86 ppm Cl, 7 ppm bicarbonate, RA=-58.
• 5.25 gallon batch

Procedure

• I added 3.9 mL of 88% lactic acid to 5.5 gallons of tap water to remove the bicarbonates, and then added 2.5 gallons of RO water to further reduce the mineral content.
• I heated the strike water to 157°, added the BrewTanB and grains, and then recirculated at 152° for 60 minutes. Next, I raised the temperature to 168° for a 10 minute mashout.
• After pulling the grains at the end of the mash, I had 7.1 gallons of runnings with a gravity of 1.035, for 74% mash efficiency. I boiled the wort (without hops) for 5 minutes and then chilled it to 95° before adding 25 mL of 88% lactic acid to adjust the pH of the wort to ~4.2.
• Before pitching the sour culture, I rehydrated it with 5 g of DME in 100 g of water. My previous experience with dry lacto cultures is that they can clump up, so rehydration seemed wise. Once this was done, I pitched the culture.
• I did the inital brew on 8 March 2026.
• Within my Foundry, I held the temperature at 100° for 48 hours, until it hit what tasted like a reasonable level of acidity.
• I boiled the wort for 60 minutes, adding hops and BrewTanB per the recipe. Then, I chilled the wort down to 70° before pitching the yeast.
• I pitched the US-05 on 10 March 2026. Around 6 gallons went into the fermenter, with a starting gravity of 1.040.
• The beer was fermented at 68°. I added the craft puree on 15 March, and also moved the fermenter to ambient at that time.
• I kegged the beer on 21 March 2026, using 3.15 oz. of corn sugar in the keg. I added the fruit powders directly at this time.
• Because it was such a large batch, I had some beer left over and bottled it with carbonation drops. The bottle did not get the TrueFruit/TrueLime additions, so is just the “base” fruit style.
• On 7 April 2026, I measured 16 psi in the keg at 68°, which is around 1.8 volumes of CO2. At this point, I moved the keg to the conditioning chamber, chilled to 34°, and used force carbonation to finish out the beer preparation.

Because I had both a bottled version (with no TrueFruit/TrueLime) and a kegged version (with the additions at kegging), I decided to write up my tasting notes separately.

Tasting – Bottled Version

• Appearance
  • Light yellow, fairly hazy beer; it pours with a rich white head that subsides fairly quickly and leaves lacing on the glass.
• Aroma
  • Lightly tart, lightly doughy, moderate tropical fruit aroma that accentuates mango.
• Flavor
  • Moderately high level of clean lactic acidity; light doughy malt character; medium level of tropical fruit flavor, especially mango, with the passionfruit behind that.
• Mouthfeel
  • Medium-high carbonation, light body, dry finish.
• Would I Brew This Again?
  • Yes! This is an awesome sour, one that is complex with the fruit, but not in-your-face. The mango is a little more obvious than the passionfruit; a touch more of the latter would be nice. The fruit quality definitely gets more noticeable as the beer warms.
• Overall
  • 9/10

Tasting – Kegged Version

• Appearance
  • Modestly hazy, shimmery, pale yellow beer that pours with a surprisingly persistent white head, which leaves some lacing on the glass.
• Aroma
  • Bright tropical fruit bouquet at a medium-high level; mango and passionfruit, absolutely! The aroma balance is slightly tilted towards passionfruit. Some lactic sourness comes through, too; light bread dough.
• Flavor
  • As with the aroma, a bright and fresh tropical fruit flavor is prominent; lime is immediately recognizable, alongside passionfruit. The mango character is a little more subdued. The beer has a clean lactic acid sourness, and a slightly doughy malt character at a low level.
• Mouthfeel
  • Light body, medium-high carbonation, slightly dry finish.
• Would I Brew This Again?
  • WOW! The keg version is simply amazing, and the blend of fruit is close to perfection. I might notch back the lime just a touch (perhaps half the amount I used) so that it’s not quite as noticeable and more in a supporting role. The TrueFruit was an excellent addition, in particular helping the passionfruit to shine. This might be one of the most fun (and most enjoyable) brewing projects I’ve had in awhile.
  • Compared to the bottled version, the fruit quality is “better” on this one. Everything else is (as expected) fairly similar.
• Overall
  • 9.5/10