Lemon basil: the citrus-scented basil Southeast Asian kitchens build around

Lemon basil smells like basil and lemon zest at once, and that single trait makes it the herb Thai, Lao and Indonesian kitchens build dishes around. It is smaller-leaved and lighter green than sweet basil, with a cleaner, sharper aroma. King Quality Produce carries lemon basil year-round in bunches, 60 to a box. Here is what it is, where it comes from, how to buy and hold it, and what the numbers say about the leaf.

What lemon basil is

Lemon basil is Ocimum × citriodorum, a hybrid of sweet basil (O. basilicum) and O. americanum⁴. The hybrid parentage is the reason it smells the way it does. In a 2017 analysis of basil essential oils, lemon basil's oil contained nerol at 23.0 percent and citral at about 20.7 percent, two compounds not detected at all in the sweet or purple basil oils tested, which led the authors to classify it as its own nerol-rich chemotype⁴. Citral is the compound responsible for the lemon aroma, as Purdue noted when it released the lemon basil variety Sweet Dani in 1998⁵.

Sweet Dani is a useful reference point for what good lemon basil should be. Bred at Purdue by James Simon and Mario Morales, it was named a 1998 All-America Selections winner; its distributor reported that it yields 70 to 75 percent more essential oil than most lemon basils with a much higher citral content, and Simon noted it does not lose much lemon flavor on drying⁵. Lemon basils in general are small-leaved types that grow 8 to 12 inches tall and wide, compared with 2 to 3 feet for the large-leaved sweet basils⁷, which is why a lemon basil bunch looks slighter in the hand than a Genovese bunch of the same stem count.

Where and when it grows

Basil is a warm-season crop that grows best between 45 and 80°F and is killed by frost; commercial U.S. basil is grown mainly in Arizona, California, Florida, New Mexico and North Carolina, and Mexico is a large exporter of basil to the United States⁷. In warm climates growers take three to five cuttings a year⁷. KQP sources lemon basil from growers in Mexico, the Southwest and California and carries it every month, with the thinnest supply in the coldest weeks of winter when field production in the desert slows.

Lemon basil is a specialty line everywhere it is grown, so volumes are small and a single grower's cutting schedule can move the market. If a Thai or Indonesian kitchen runs lemon basil on a signature dish, a standing weekly order protects you better than buying off the floor.

How to buy lemon basil: bunches and receiving

Lemon basil comes in bunches, 60 bunches to a box, and we quote by the box. Growers harvest before bloom and keep bunches loose so air can move through them³. UC Davis's quality indices for culinary herbs apply: freshness, uniform size, form and color, no yellowed or damaged leaves, no decay, insect damage or wilting, and a strong characteristic aroma². With lemon basil the aroma check is most of the inspection. The citrus note should be obvious from arm's length when you open the box; if you have to hunt for it, the basil has been chilled or has sat too long.

Chilling injury on basil shows as blackened leaves, stem discoloration and loss of aroma³, or as browning of the leaves and growing tip, bronzing of the veins and loss of gloss². Lemon basil's small, pale leaves show the browning plainly, so a glance at the top of the bunch tells you most of what you need. Flower spikes in the bunch mean the field was cut late, since growers are meant to harvest before bloom³; a few are acceptable, a bunch that is half flowers is not.

• Open the box and smell for citrus at arm's length
• Leaves pale green and glossy, no brown or black tips
• Stems firm, not dark or slimy
• Few or no flower spikes
• Bunches loose and dry, not packed tight and wet

Storage and shelf life

Store lemon basil like every basil: warmer than you think. UC Davis recommends 32°F for most culinary herbs but says basil is chilling sensitive and should be stored above 50°F, at relative humidity above 95 percent, with one to two weeks of shelf life depending on water loss². Rutgers puts the optimum at 55°F and 90 to 95 percent relative humidity, citing UC Davis research in which basil held at 50 to 68°F for ten days kept markedly better visual quality than basil at 32°F³.

Keep bunches loose, stand the stems in water or cover them loosely, and never let the leaves touch ice³. Basil is minimally affected by ethylene, so it can sit near ripening produce². Cold is the enemy, and so is time: storage at chilling temperatures greatly reduces basil's aroma quality, and aroma declines in storage even when the herb is handled well². For an herb whose entire value is its smell, that argues for buying twice a week rather than once.

Nutrition by the numbers

USDA FoodData Central has no separate entry for lemon basil; its entry for fresh basil reports, per 100 g, 23 calories, 92.1 g water, 3.15 g protein, 2.65 g carbohydrate, 1.6 g fiber, 177 mg calcium, 3.17 mg iron, 64 mg magnesium, 295 mg potassium, 1.15 mg manganese, 18 mg vitamin C, 68 µg folate, 264 µg vitamin A (RAE), 3,142 µg beta-carotene, 5,650 µg lutein plus zeaxanthin and 414.8 µg vitamin K¹. Against FDA's Daily Values of 120 µg for vitamin K, 2.3 mg for manganese and 90 mg for vitamin C⁸, 100 g of basil carries more than three times a day's vitamin K, about half a day's manganese and 20 percent of a day's vitamin C. A handful of leaves is a small fraction of 100 g, and these are measurements of the leaf, not health claims.

Lemon basil does differ from other basils in one lab measure. In a 2002 Rutgers study, the lemon basil tested (Sweet Dani Lemon, O. citriodorum) had 55.8 mg of total phenolics per gram of dry leaf and antioxidant readings among the lowest of the green cultivars, well below the purple basils, and its essential oil yield was 1.1 ml per 100 g of dry weight⁶. Lemon basil is bought for its aroma, not for its phenolics, and the numbers agree.

In the kitchen: how Los Angeles uses lemon basil

Thai Town, the San Gabriel Valley and the Indonesian and Lao kitchens scattered across the county are the core buyers. Lemon basil goes in raw at the end of soups and curries, is eaten by the sprig with grilled fish and rice, and turns up in salads and dipping sauces where the citrus note does the work a squeeze of lime would otherwise do. Indonesian cooks pair it with grilled and fried fish; Lao and Isan kitchens finish soups and stews with it.

Outside Southeast Asian cooking, pastry kitchens and bars use it where lemon verbena would go: syrups, sorbets, granita and gin drinks. Add it raw or in the last seconds of heat, because the citral and nerol that make it lemon basil are volatile oil components and leave with the steam. Markets serving Southeast Asian neighborhoods sell it in bunches next to Thai basil, mint and culantro, and the same rule holds on the shelf: no ice, no mist, and out of the cold case.

Lemon basil is on our list every week of the year. Call the office at (213) 627-7181 or email office@kingqualityproduce.com for this week's counts and bunch sizes.