Collage by Amy Morrison

[Nick Keane is the presiding barman at the soon-to-open Pearl District location of Tilt, as well as a freelance beverage consultant.—Eds.]

IT SEEMS that every mid-tier Portland watering hole has some kind of infusion going on. This tends to be the brainchild of a well-meaning yet uninformed bartender who was handed some overripe fruit, cheap vodka, and an edict to turn them into Cash™. Let's explore a more scientifically sound—and generally less faulty—method that has been pioneered over the last few years.

Nitrous oxide, when used as a pressurizing agent in a soda siphon, has the tremendous benefit of yielding more reproducible and consistent results than the traditional method of soaking fruits or spices in the spirit for weeks (a method that suffers from constantly changing temperature and light conditions that affect the extraction rate).

To get started, you'll need to pick up a soda siphon and some nitrous chargers. I recommend the ISI brand, but if you want a more stylish one, there are plenty of old-school glass ones floating around the internet. The thumb-sized nitrous canisters—commonly sold as whipped cream chargers—can be procured at Cash and Carry, Sur La Table, and restaurant supply stores like Rose's and Pitman. They're also often found at shady bodegas.

The process is fairly straightforward, but needs special attention in two areas: time and ingredient measures. This process tends to take less than 10 minutes. I've also given ingredient guidelines in the recipes that follow.

Once you have decided on a base spirit and flavoring adjuncts, the process is dead easy. Simply add all the ingredients to the siphon (leaving proper head space, so the canister will reach maximum PSI), and charge according to the manufacturer's specs. Assuming a standard ABV of 40%, I usually start with a charge time of five minutes, and if it needs more "dwell" time (contact with gas) to get to the flavor you want, it's simple enough to crack a second canister into the same batch (don't worry, it won't explode). A timer is a good idea, as is giving the canister a few good shakes to help dissolve the nitrous into the liquid. As far as what to start with, I'd recommend hard spices (cracked, not ground), citrus peels, and fresh, leafy herbs. For base spirits, gin and vodka are the most accepting and forgiving. I highly recommend keeping notes to aid your learning curve.

One of the most important things is to fine strain after you're finished, and bottle in an airtight container to preserve the freshness. Most infusions will keep for several months, with those made of fruit or vegetables lasting about one month. Refrigeration will lengthen this timeframe.

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Charge It: Lemon Verbena Gin

750 milliliter bottle of Gordon's London dry gin

25 grams fresh lemon verbena leaves (picked clean of brown leaves and stems)

Zest of ½ lemon

Zest of ½ lime

Lightly muddle zests and verbena. Add to siphon with gin. Seal, charge with nitrous, and keep sealed for 5-6 minutes, while shaking every couple minutes. Taste, correct if needed, and bottle.

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What to make with that? How about...

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Use It: Jus de Vie

1 ½ ounces lemon verbena gin

¾ ounce Montinore Verjus

½ ounce St. Germain

1 dash Fee Brothers

celery bitters

Stir all ingredients with ice, strain into cocktail glass. No garnish.

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Charge It: Hackavit

750 milliliter bottle of Monopolowa vodka

20 grams caraway seed, toasted

10 grams each of cardamom, anise, cumin

5 grams grains of paradise and juniper berries

Zest of 1 lemon

Add all spices and vodka to your siphon and charge with nitrous for 10-12 minutes. Shake several times during the process. Fine strain and bottle. Let sit for 24 hours before using to allow flavors to meld.

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Use It: Vikings of the

Willamette

1 ¾ ounces infused vodka

¾ ounce Combier triple sec

½ ounce Hammer & Tongs L'Afrique vermouth

¼ ounce Fernet-Branca

Stir all ingredients with ice and strain into cocktail glass (rinsed with a peated scotch or smoky mezcal for an optional twist). Garnish with a twist of orange.