Hibiscus Flower: Tea, Powder, Agua de Jamaica and Blood Pressure

Our bulk hibiscus supplier notes that hibiscus may be grown alongside peanuts and may contain peanuts or shell fragments. If you have a peanut allergy, avoid it.

What is the hibiscus used for tea?

The hibiscus in tea is roselle, Hibiscus sabdariffa, a frost-tender plant in the mallow family grown in tropical and subtropical regions. Other names include Jamaica sorrel, red sorrel, sour tea, karkade and rosa de Jamaica.

Despite the name "flower," the part you buy is the calyx. After the yellow flower drops, the ring of sepals at its base swells into a fleshy, bright red cup around the seed pod. That calyx is harvested and dried. The horticulturist Julia Morton pointed out that calling it "flor de jamaica" leads many people to think they are buying petals (Morton, Fruits of Warm Climates, Purdue University NewCROP).

Its tart taste comes from organic acids, including hibiscus acid and hydroxycitric acid. Its color comes from anthocyanins, chiefly delphinidin-3-sambubioside and cyanidin-3-sambubioside (Da-Costa-Rocha et al., Food Chemistry, 2014). Those same red pigments are why food makers have looked at roselle as a natural colorant in place of synthetic dyes.

Whole, cut, powder or tea bags: which form?

How to make hibiscus tea and agua de jamaica

One tip from Morton's notes matters more than any recipe: dried calyces give up their full color and flavor when boiled, not just steeped. A short simmer makes a much richer drink.

Agua de jamaica (our everyday version)

1. Rinse 1/2 cup of whole dried hibiscus.
2. Add it to 4 cups of water, bring to a boil, then simmer for about 5 minutes.
3. Turn off the heat and let it steep until the liquid is deep ruby, 15 to 20 minutes.
4. Strain into a pitcher, add 4 more cups of cold water, and sweeten to taste with sugar, honey or agave.
5. Chill and serve over ice.

For a single cup of hot tea, simmer 1 to 2 teaspoons of cut hibiscus in a cup of water for a few minutes, or steep a tea bag. In Jamaica, a holiday version is made by pouring boiling water over roselle with grated ginger and sugar and letting it stand overnight; in Egypt, karkade is drunk cold in summer and hot in winter (Morton).

Ways to use hibiscus flower powder

• Smoothies and drinks. Blend a small spoonful into a fruit smoothie or lemonade for color and tartness.
• Natural pink and red color. Stir into frosting, yogurt, chia pudding or icing. Start small; the flavor is sharp.
• Sauces and syrups. Roselle cooked with sugar tastes and looks much like cranberry sauce, and calyces contain enough pectin to set a jelly without added pectin (Morton). Roselle syrup has long been poured over pancakes, waffles and ice cream.

Does hibiscus tea lower blood pressure?

Hibiscus is one of the better-studied herbal teas for blood pressure, but the evidence is still modest and mixed in quality.

• McKay et al. (Journal of Nutrition, 2010). 65 adults aged 30 to 70 with prehypertension or mild hypertension, not on blood pressure medicine, drank three 240 mL servings of hibiscus tea or a placebo drink daily for 6 weeks. Systolic pressure fell 7.2 mmHg with hibiscus versus 1.3 mmHg with placebo. The drop in diastolic pressure was not significantly different from placebo. People who started with higher readings saw larger drops.
• Meta-analyses. Pooling 5 trials (390 people), Serban et al. (Journal of Hypertension, 2015) found systolic pressure about 7.6 mmHg lower and diastolic about 3.5 mmHg lower. A 2022 review of 17 trials found a similar systolic effect versus placebo, largest in people with raised blood pressure (Ellis et al., Nutrition Reviews).
• The cautious view. A 2021 Cochrane review, using stricter entry rules, found only one eligible trial and judged the evidence too weak to say whether roselle lowers blood pressure in people with hypertension (Pattanittum et al.).

The fair summary: hibiscus tea may modestly lower blood pressure, especially when it starts high, but trials are small and varied. It is not a replacement for prescribed treatment. If heart health is your interest, our guide to hawthorn covers another traditional herb in this area.

Safety and interactions

A major review describes hibiscus as having an excellent safety and tolerability record as a food and drink (Da-Costa-Rocha et al., 2014). Points to keep in mind:

• Blood pressure medicines. Because hibiscus may lower blood pressure, it could add to the effect of prescription drugs. In rats and rabbits, hibiscus extract raised blood levels of the diuretic hydrochlorothiazide and increased urine output (Ndu et al., Journal of Medicinal Food, 2011). In rats, it lowered blood levels of captopril (Nurfaradilla et al., 2020). These are animal studies, but they are a good reason to talk with your doctor or pharmacist first.
• Pregnancy. Human safety data are lacking. In a rat study, drinking hibiscus extract during pregnancy was linked to later puberty and higher body weight in the offspring (Iyare and Adegoke, 2008). Ask your provider before using it regularly.
• Peanut allergy. See the supplier's cross-contact note at the top of this page.

Find it at William's

• Starwest organic hibiscus flower powder, sold by weight in our bulk section, for smoothies, color and baking.
• Starwest organic hibiscus flowers, cut and sifted, sold by weight, for hot tea and blends.
• Starwest organic whole hibiscus flowers, sold by weight, the best pick for agua de jamaica.
• Traditional Medicinals hibiscus tea, 16 bags: organic and caffeine-free.

In store you can weigh out exactly as much bulk hibiscus as you want; online orders ship in prepacked amounts, typically 1 lb. Hibiscus blends well with rose hips, and for another color-changing tea, try butterfly pea flower.

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