Cherry Kvass Zefir
Where wild fermentation meets the architectural precision of modern pastry
This recipe explores the deep complexity of cherry through three distinct dimensions: fresh (raw puree in the meringue), heat-treated (cooked in the syrup), and fermented (via our house-made cherry kvass). The result is a sophisticated, aerated confection with a mild lactic tang and a fermented malt finish.
This recipe is developed by Irina Pashkova, the visionary pastry chef behind the signature flavor architecture of Cosmos Society. As the co-author of the Fermentation in Desserts guide, Irina’s work exists at the precise intersection of microbial science and high-confectionery architecture. Her work exists at the precise intersection of microbial science and high-confectionery architecture, where flavor is treated as a structural element rather than a mere additive. By utilizing deep fermentation cycles and rigorous technical standards, Irina moves beyond traditional sweetness to redefine the sensory and textural boundaries of modern pastry.
For us, authenticity is non-negotiable: our kvass is fermented exclusively with a sourdough starter, relying on wild cultures to unlock that signature depth.
Note: If you don’t have access to house-fermented cherry kvass, substitute with a high-quality, sourdough-based (lacto-fermented) kvass.
Cherry Kvass Zefir Recipe
Ingredients
Meringue Base
100g Apple Puree (High pectin, reduced)
30g Cherry Puree
8.5g Egg White Powder (Albumin)
70g Fine Granulated Sugar
Cooking Syrup
200g Fine Granulated Sugar
50g Glucose Syrup (43 DE)
9g Agar-Agar (900 Bloom)
185g Cherry Kvass (or plain sourdough kvass)
40g Cherry Puree
Finishing
Dextrose or Icing Sugar (for coating)
Method
Hydration: Combine apple puree, 30g cherry puree, and albumin in a stand mixer bowl. Allow to hydrate for 10-15 minutes. Stir in 70g sugar.
Syrup Prep: In a heavy-bottomed saucepan, combine all syrup ingredients. Begin cooking over medium heat, stirring constantly to activate the agar-agar.
Aeration: While the syrup heats, begin whipping the puree mixture. Start on medium, increasing to maximum velocity until the mass achieves stiff peaks and high density.
Thermal Concentration: Cook the syrup to 110C. It should reach a "heavy thread" stage, falling from the spatula in slow, viscous droplets.
Emulsification: With the mixer on high, pour the hot syrup into the meringue in a steady, thin stream. Continue whipping until the temperature drops to 50–55C and the whisk leaves sharp, permanent tracks.
Depositing: Quickly transfer to a piping bag. Pipe onto parchment immediately, as the agar begins to set below 40C.
Stabilization: Allow to stabilize at room temperature for 12–24 hours (depending on humidity) until a dry "skin" forms.
Finishing: Pair the halves and dredge in dextrose or icing sugar to neutralize tackiness. Store in an airtight container for 5–7 days.
Most people think of flavor as a single note, but in professional pastry, we build it like a chord. For this zefir, we’ve deconstructed the cherry into three distinct states to create a profile that is as complex as a fine wine:
The Fresh Dimension (The Brightness): By using frozen cherry puree in the meringue base, we preserve the volatile aromatic compounds and the natural acidity of the fruit.
The Thermal Dimension (The Depth): In the syrup phase, we heat-treat the cherry. This caramelizes the natural sugars and creates a jammy, deep "base note" that grounds the sweetness.
The Fermented Dimension (The Soul): Using our lacto-fermented Cherry Kvass introduces a mild lactic tang and a malty, funky complexity you simply can’t get from fruit alone. It’s the secret to that sophisticated, "grown-up" finish.
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Denis Pashkov
Irene Pashkova
cosmos society