Guest Post: Aaron Polsky & Lacto-Fermented Citrus

Guest Post: Aaron Polsky & Lacto-Fermented Citrus

The first in our Guest Post series, it’s only fitting that honour falls with one of our dear friends and earliest supporters, Aaron Polsky.

Having hosted the first ever Trash Tiki pop up in LA late 2016, we somehow attempted to return the favour the following March when Aaron came for a guest shift at WastED, the pop up we did on the rooftop of Selfridges alongside Dan Barber & Blue Hill Stone Barns Team. He brought this recipe with him then and we’ve been telling any & all who’ll listen about it ever since.

We’ve see a few versions of “fermented citrus” where people just throw juice and/or husks in a tub with sugar and let it sit for a few days. This does nothing and if anything, is dangerous. Controlled fermentations (i.e. everything measured & selecting a cultivated bacteria based on your desired outcome) are the only type anyone should be attempting.

A great recipe that finds an excellent use for old citrus juice, a common waste item in many bars, we also love the fact this is outrageously simple to execute. Over to you Polsky….

“Bars that use fresh citrus juice waste several gallons a week—it's an uncomfortable and inconvenient fact. At Harvard and Stone, we've slowly started to implement a system that gives a second use to this juice. We're lacto-fermenting our two-day old lemon and lime juice into citrus soda, sometimes with the addition with flat champagne and tired citrus garnish for extra complexity and waste-fighting power.

 Despite lemon and lime's high acidity, it's easier than it sounds.

Lacto Fermented Citrus
Here's what you need:

• Fermentation Bucket
• Airlock
• Sani Solution
• Whisk
• Scale (1-1000g, .1g precision)
• Probiotic capsules from a vitamin store. The cheapest kind is fine, provided it's unflavored.


 1. Make a sanitizer solution as per the instructions on the bottle. Reserve part of this to fill your airlock. Sanitize the rest of your equipment with it, then allow to air-dry as per the instructions on the bottle.
2. To your bucket, add 2-day-old lemon juice, lime juice, flat champagne, and tired lemon and lime wedges that you may have laying around.
3. Add sugar to the liquid, 250g for every 1L of liquid. Whisk until dissolved.
4. Open up 3 probiotic capsules for every liter of liquid, and empty them into the bucket. Whisk vigorously.
5. Cover the bucket, fill your airlock with diluted sanitizer solution, and carefully, making sure no sanitizer drips back into the bucket, insert the airlock into the rubber grommet.
6. Allow to sit at room temperature for 7±2 days. At that point the juice should be fizzy, bright, and should taste like an ultra-dry lemon soda. At about 3 days, it tastes like old juice—the transformation is not yet complete. I've never let it go past 9 days.

 By adding sugar, you're making the environment more hospitable to the probiotics used to ferment the juice—without it they wouldn't be able to flourish, reproduce, or create new flavors in the high-acid environment.. We like to use this soda to top up our kegs of cocktail (usually a mule or a paloma) in place of water. This reduces the citric acid and malic acid we'd need to normally use to almost nil, depending on how much yield we get per week (usually it's enough!).

 Thanks to this technique, our cocktails are more delicious for our guests, and we get closer to using every component of our prep.”


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