Coming across unusual, briefly-in-season, quick-spoiling fruit at Monterey Market yet again inspires cold-infused shrubs to extend the experience.
Fresh kaffir limes, unlike any other citrus in fragrance:
Oleo saccharum yields the most intense flavors (shown here, Yuzu, an east asian citrus):
It’s a pain to juice a yuzu:
And a week later I strained and bottled them (I didn’t have time for real labels):
After last year’s enjoyable experience making shrubs (a shelf-stable way to preserve fruit with vinegar and sugar, for mixing into soda water, cocktails, salad dressings, and so on), I’ve spent a few more weekends trying new citrus, new vinegars, and different ratios, as well as using oleo saccharums (citrus oils extracted from the peel with sugar: I posted some photos of the process yesterday).
Bergamot / Cider Vinegar Shrub
Since much of the unique flavor of bergamot is in the zest, an oleo saccharum is key. I combined the peel of four bergamots with 2/3 cups of white sugar (let sit and periodically kneaded for about 10 hours, see photos)– by the end of that time I could smell it even through the bag. I added that to the juice of 17 bergamots (about 2 cups), another 1 1/3 cups white sugar, and, by trial and error, 3/4 cups of my favorite cider vinegar (Bragg).
The vinegar flavor was a little overpowering, initially, but it’s supposed to mellow over time… and indeed, after sitting for a week it’s become one of my favorite shrubs– one spoonful livens up a glass of sparkling water.
Kaffir Lime Shrub
I’d been brought a gift of fresh kaffir limes (which I’d never seen before), just on the edge of turning brown, and knew immediately I wanted to preserve their flavor with a shrub. The peel has the same distinctive scent as kaffir lime leaves, a dry, spicy, and floral citrus.
Since they’re so knobby, they were a huge pain to peel– normal peelers or zesters were useless, so I used a small knife and painstakingly trimmed off rind and then removed pith… ending up with the peel of 15 kaffir limes packed in 1/2 cup sugar to make an oleo saccharum, plus the juice of the limes (only half a cup, quite dry), and almost 1/2 cup of a very mild neutral rice vinegar. This gave me a dry, perfume-like shrub that’s great to splash into water or champagne.
Calamansi Lemongrass Shrub
I don’t have the exact proportions written down, but this excellent shrub (probably my favorite basic citrus shrub) combined tiny calamansi (which I just sliced in half and packed in sugar, extracting both oleo saccharum and juice), additional lime juice, half a stalk of finely-sliced lemongrass, sugar, and champagne vinegar.
Meyer Lemon Peppercorn Shrub
The peel of 9 meyer lemons in ⅔ cup sugar, the juice of 18 (about 2 cups), another 1 ⅓ cups sugar, mint leaves, black peppercorns, and a mix of cider and white vinegars. Easy.
I’m looking forward to exploring further this summer once non-citrus fruits are in season…
This is now my favorite way to extract intense citrus flavors, especially from fragrant citrus (bergamot, other sour oranges, kaffir limes, and so on). I’ve started using this in both shrubs and [citrus]cellos. Basically, you slice the peel off citrus, painstakingly scrape off any white pith so you have thin, translucent strips of peel, then pack them in sugar for about 10 hours, periodically kneading them as the oil diffuses out of the peel and liquefies the sugar. Bergamot through the afternoon, in photos: 
And knobby kaffir limes getting the same treatment (I spent more time after the first photo removing pith before packing in sugar): 
I’m more into beer, but an A+ cocktail at Millenium: “House Infused Manchurian Crabapple & Chipotle Tequila, Kaffir Lime, Pomegranate, Cane Syrup, Peychaud’s Bitters”. A tart and smoky slow burn.
Cue grainy cell phone photo:
The Robot Must Eat 