Catharina Sour: The Tropical Spirit of Brazil

In the world of professional brewing, most “Regional” styles take centuries to evolve—think of the Belgian Gueuze or the British Bitter. But in 2016, a group of brewers in the Santa Catarina region of Brazil decided they wanted a style that belonged uniquely to them. They took the skeleton of a German Berliner Weisse and injected it with the vibrant, tropical soul of the Amazon.

The resulting style, Catharina Sour, became the first Brazilian beer style to be included in the BJCP guidelines (Category X4).

A Catharina Sour is an explosion of “Bright Fruit.” It is not just a “Fruit Beer”—it is a technically rigorous exercise in Acidity Management. It must be light, dry, and sharply sour, acting as a canvas for the intense aromas of passionfruit, guava, mango, and pitaya.

In this guide, we will analyze the technical history of the style, the science of local fruit maceration, and the “authority” methods for achieving a clean, probiotic acidity.

1. The Origin: A Modern Collaboration

The Catharina Sour was born from a desire for “Tropical Refreshment.”

The Problem: Brazilian brewers loved the acidity of Berliner Weisse, but they felt the style was too “thin” and “wheaty” for the Brazilian palate. They also felt it lacked the “visual impact” needed for a tropical market.
The Solution: By increasing the ABV (to 4% - 5.5%) and adding astronomical amounts of whole fruit, they created a beer that could stand up to the heat of a South American summer while showcasing the local agricultural bounty.

2. Technical Profile: BJCP Standards (Category X4)

The Catharina Sour is characterized by its “Clean” acidity and its “Fruit Forward” intensity.

Parameter	Targeted Range
Original Gravity (OG)	1.036 – 1.048
Final Gravity (FG)	1.004 – 1.012
ABV	4.0% – 5.5%
Bitterness (IBU)	2 – 8
Color (SRM)	2 – 6 (Plus the color of the fruit)

Sensory Breakdown

Visual: Typically hazy (due to fruit solids). The color must represent the fruit added—a Guava Catharina should look like pink grapefruit juice; a Pitaya version should look neon purple.
Aroma: A “wall” of tropical fruit. The character should smell like fresh, ripe fruit, not a syrup. There is zero hop aroma.
Flavor: Sharp, clean, lactic acidity. The malt is a simple “white bread” background. The finish is short and dry—you want another sip immediately.

3. The Acidity Science: Kettle Souring with Precision

To achieve the “Clean” profile of a Catharina Sour, authority brewers use Kettle Souring.

The Process:

The Mash: A 50/50 blend of Pilsner Malt and Wheat Malt.
The Boil (Min.): Boil for 10 minutes to sanitize the wort.
The Cooling: Cool the wort to 38°C - 42°C.
The Inoculation: Pitch a pure culture of Lactobacillus plantarum.
The Håll (The Hold): Seal the kettle (purge with CO2 to prevent oxidation). Let the bacteria work for 12-24 hours.
The Target: Stop the souring when the pH reaches 3.2 - 3.4.
The Final Boil: Re-boil the wort to kill the bacteria and add a tiny amount of bittering hops.

Technical Tip: If you let the pH drop below 3.1, the yeast will struggle to ferment the beer, leading to a “sickly sweet” and unfinished product. Precision pH monitoring is the hallmark of the Catharina master.

4. The Fruit Strategy: Whole Orchard in a Tank

This is where the style moves from “Sour Beer” to “Catharina.”

Quantity: Use at least 150g to 200g of fruit pulp per liter.
The Fruit Choice: The most authoritative versions use tropical fruits with high acidity and color. Maracujá (Passionfruit), Butiá, and Pitanga are the gold standards.
Timing: Add the fruit during the tail end of primary fermentation. This allows the yeast to “scrub” any oxygen introduced by the fruit, preventing the “dirty dishwater” brown color of oxidation.

5. Technical Case Study: The Maracujá Paradox

Passionfruit (Maracujá) is the most popular fruit for this style, but it is also the most dangerous.

The Problem: Passionfruit is naturally very acidic. If you kettle-sour your beer to pH 3.2 and then add passionfruit, the total acidity can become “chemical” or “stinging,” destroying the drinkability.
The Authority Correction: When brewing with high-acid fruit, stop the kettle sour at pH 3.6. Let the fruit provide the final 0.4 pH drop. This results in a “softer,” more integrated acidity that feels natural on the palate.

6. Distinction: Catharina Sour vs. Berliner Weisse

Feature	Catharina Sour	Berliner Weisse
ABV	4.0% – 5.5% (Stronger)	2.8% – 3.8% (Lighter)
Fruit	Non-negotiable (Intense)	Optional (Added in glass)
Acidity	Purely Lactic (Clean)	Lactic + Funky (Often complex)
Haze	Fruit-driven opacity	Wheat-driven chill haze

7. Food Pairing: The Tropical Party

The high acidity and low bitterness make this beer a “Palate Resetter.”

Appetizer: Ceviche
- The citrus juices in the ceviche find a “mirror image” in the beer’s acidity, while the tropical fruit aroma complements the fresh fish.
Main: Spicy Acarajé (Fried Bean Cakes)
- The sharp sourness of the beer cuts through the “Heavy” palm oil (Dendê) used in Brazilian street food.
Dessert: Cheesecake
- The beer acts as the “Fruit Topping” for the creamy, fatty cheese.

8. Draft Science: Managing the Fruit Sludge

Because of the massive fruit additions, Catharina Sours can be a nightmare for draft systems.

The Filtration: Professional brewers use a Centrifuge or a very coarse filter to remove the largest fruit fibers while preserving the “Glowing” color.
Draft Pressure: Serve at a high pressure (12-14 PSI) to maintain the “Zesty” carbonation. A “flat” fruit sour tastes like spoiled juice.

9. Advanced FAQ: Professional Insight

Q: Can I use fruit purees or syrups? A: You can, but to reach the Authority Level, you should use fresh pulp. Purees often contain preservatives that can “stun” the yeast and lead to off-flavors. Fresh pulp provides a “Bigger” aroma that purees cannot mimic.

Q: Why does my Catharina Sour smell like “Old Cheese”? A: This is a classic kettle sour flaw. It means oxygen entered the kettle during the Lactobacillus phase, allowing Butyric Acid bacteria to take hold. (See our Guide to Off-Flavors). Always purge your kettle with CO2!

Q: Is “Dry Hopping” allowed? A: Generally, no. The “Fruit” should be the only aromatic star. Adding Citra or Mosaic to a Catharina Sour turns it into a “Fruit IPA,” which is a different category of intensity.

10. The “Neon” Effect: Expert Tip

To get that “Neon” glow in your Dragonfruit (Pitaya) or Raspberry Catharina, you must manage your Water Carbonates. Keep your Bicarbonate levels under 20 ppm. High carbonates will “Buffer” the acidity and turn the brilliant red pigments of the fruit into a dull, muddy purple. Soft water is the “Magnifying Glass” for fruit color.

11. The Future of the Style

The Catharina Sour is the leading edge of the “Modern Sour” movement. It represents a shift away from the “Vinegar” sours of the past toward “Fruit-Juice” sours that appeal to a younger, more diverse audience.

By mastering the Catharina Sour, you are proving that you can manage the extreme biology of wild bacteria and the physical chaos of whole fruit—and turn it into a liquid that is, quite simply, “Brazil in a Glass.”

12. Tropical Terroir: The Seasonality of the Amazon

To brew a truly authoritative Catharina Sour, you must respect the Fruit Ripe Cycle.

Passionfruit (Maracujá): Best used when the skin is wrinkled, signaling peak sugar and acid concentration.
Guava (Goiaba): Must be used at the “Soft-Touch” phase to ensure the maximum release of aromatic esters.
The Technical Impact: Because tropical fruits vary in sugar content (Brix) throughout the year, the brewer must adjust the base beer’s gravity for every batch. A “Static” recipe is the mark of a hobbyist; a “Reactive” recipe is the mark of a Catharina master. This attention to the harvest is what makes the style so fundamentally Brazilian.

Conclusion

The Catharina Sour is a technical triumph of collaboration. It is a beer of “Maximum Impact”—high color, high aroma, and high refreshment.

Drink it fresh, serve it cold, and always celebrate the harvest. Next time you want to “Wow” a crowd, skip the IPA. Pour a neon-purple Catharina. The world is watching Brazil, and the view is delicious.