Roselle
Also known as hibiscus, dried hibiscus, hibiscus flowers, flor de jamaica, jamaica, red sorrel
Quick answer
The fleshy red calyx of a tropical hibiscus, dried. It is sour from organic acids and red from anthocyanins, and most of it is boiled into drinks such as karkade, bissap and agua de jamaica. In West Africa the calyx and the sour leaves also go into sauces.
- Tastes of
- sour, tart
- Heat
- Scoville does not apply
Other names
What this spice is called elsewhere, and where the translation is not clean.
karkade
Arabic — Egypt, Sudan and North Africa
bissap
Language not stated — Senegal
The handbook lists bissap among the French and English names and records it in Senegal for the plant and for the chilled juice made from the calyx.
oseille de Guinée
French
jamaica
Spanish — Mexico
The name of the dried calyx and of the drink, not a reference to the island.
asam susur
Malay
krachiap
Thai
bụp giấm
Vietnamese
Flavour and aroma
Sour. The handbooks describe the drink as sour and refreshing and the calyx as very tart, needing a good deal of sugar; the leaves are sour too. A review attributes the acid taste of the calyx to its organic acids.
No panel’s description of the smell was read. One study of a Malaysian cultivar measured the volatile compounds of fresh and dried calyces. The fresh calyx was richest in terpenes, linalool above all, with green-smelling aldehydes and fruity esters; every drying method cut these sharply and raised furans such as furfural. Its authors expect dried calyx to smell less fruity, floral and green than fresh and more caramel-like, which is an expectation from the compounds and not a tasting.
Dark red to purple calyces, which give a bright red liquid when boiled. The red is an anthocyanin colour and depends on acidity: in one study an extract was dark red at pH 1, lighter red by pH 4, nearly colourless at pH 5 and blue at pH 7. The extract itself stood at about pH 2.2.
Taste, smell and sensation, channel by channel
Smell, taste and the chemical sense of heat and cold are different senses. Each is listed with the compounds evidenced as producing it.
Smell
- Fruity
- Sweet-aromatic
- Herbal
What trained tasters smelled in drinks made from the dried calyx. A panel in Porto, describing infusions, syrups and concentrates, settled on a smell of hibiscus itself and, beside it, of aronia or cranberry, sour cherry and raisins; raspberry fitted only an instant drink. The hibiscus smell varied widely between drinks and the fruit notes were moderate or weak. This is a tasting panel’s description of drinks, not of the dry calyx, and not an analysis of its volatile compounds.
The same panel kept honey and cold black tea as descriptors of the smell of roselle drinks, at moderate or low intensity.
The same panel kept hay as its one herbaceous descriptor, at moderate or low intensity. An earlier panel of seventeen in Dakar had used a single word for the smell, that of hibiscus, and a second for a fermented smell that marks a spoiled drink.
Taste
- Sour — Hibiscus acid, Malic acid, Citric acid
The calyx is sour, and very tart when boiled into a drink. Hibiscus acid was the main compound in hot-water extracts of dried calyces from sixteen places in India, at about 10 to 15 per cent of the dry powder. A Mexican study that measured five other acids in three varieties found them in far smaller amounts, between about 0.2 and 0.6 g per 100 g of dry calyx in all: succinic most, then malic, tartaric, citric and oxalic. A handbook’s figure of about 4 per cent citric acid is not borne out by it. Drinks made from the calyx in Senegal measured pH 2.5 to 2.8, and a tasting panel there defined their acid taste as that of lemons. No source tasted the acids separately.
- Bitter
Trained tasters scored bitterness and a drying, astringent feel in drinks made from the calyx, both at moderate or low intensity, both rising with the acid taste and falling as sweetness rose.
The fresh calyx is fleshy and high in pectin, so jams and jellies made from it set readily. The leaves and green calyces give a rather mucilaginous soup.
Colour
— AnthocyaninsRed from anthocyanins, chiefly delphinidin-3-sambubioside and cyanidin-3-sambubioside. One lot of dehydrated calyces held about 362 mg per 100 g. The colour depends on acidity: an extract was dark red at pH 1, lighter red by pH 4, nearly colourless at pH 5 and blue at pH 7, and heating in a low-acid liquid destroyed the pigment far faster than heating in an acid one. Cultivars without anthocyanin have pale green calyces.
The fresh calyx is fleshy. It is rich in pectin, which is why it sets readily into jams and jellies, and the leaves and green calyces give a rather mucilaginous soup.
Heat
Pungency scale: none — this spice is not pungent
No heat.
- Citric acid — Named among the organic acids behind the sourness, and put by one handbook at about 4 per cent of the calyx. The one study read that measured it found far less: 4 to 29 mg per 100 g of dry calyx in three Mexican varieties.(what citric acid is)
- Malic acid — Measured in the same three Mexican varieties at 64 to 165 mg per 100 g of dry calyx, second to succinic acid among the five acids that study measured. It did not measure hibiscus acid.(what malic acid is)
- Hibiscus acid — The main compound in hot-water extracts of dried calyces in one study, at about 10 to 15 per cent of the dry powder. A review describes it as a lactone and as a diastereomer of garcinia acid, the lactone of the Garcinia fruits: the same atoms, arranged differently in space.(what hibiscus acid is)
- Anthocyanins — The red. Delphinidin-3-sambubioside and cyanidin-3-sambubioside are the two main pigments of the calyx; a review puts the first at 85 per cent of the total.(what anthocyanins is)
The review reports what earlier analyses found and was written about pharmacology; it is cited for which acids and pigments are present and not for anything they are said to do.
Pairings
Ranked by how well established the combination is, with the reason and the caveats attached.
Other spices and blends
Ginger
StrongThe handbook account of roselle in Africa records that ginger is sometimes added when the calyces are boiled for the chilled juice sold as bissap in Senegal and da bilenni in Côte d’Ivoire, Mali and Burkina Faso, particularly when the juice is to be sold frozen.
How: Boiled together for bissap or da bilenni
Add alongside: Mint
The handbook says “sometimes”; this is an addition some sellers make, not a fixed part of the drink.
Mint
StrongRecorded in the same sentence as ginger: mint is sometimes boiled with the calyces for the chilled or frozen juice sold in West African markets.
How: Boiled together for bissap or da bilenni
Add alongside: Ginger
The handbook says “sometimes”; this is an addition some sellers make, not a fixed part of the drink.
Preparation and use
Boil the dried calyces in water until the liquid is deep red, strain, and sweeten; the calyx is very tart. Keep it in an acid liquid if the red matters: the colour held for hours of heating in acid and was lost within half an hour at neutral pH.
Mostly drunk: the dried calyces are boiled into a sour red tea or juice, taken hot or cold and sweetened, or boiled down to a syrup. They are also made into jams and jellies, which set well because the calyx is rich in pectin. As a kitchen ingredient the calyces and the sour leaves go into West African sauces and soups, the stewed green calyx is a condiment for rice in Senegal, and the powdered dried calyx seasons sauces in Côte d’Ivoire. The seed is eaten roasted, ground into meal or fermented; the handbooks add that it needs proper processing first, and that its oil holds cyclopropenoid acids which they describe as toxic. That concerns the seed and its oil, not the calyx.
- boiling — Boiling in water is how the calyx is used: it gives up its acid and its red together. In an acid liquid the colour holds. Heated at pH 2, an extract kept 88 per cent of its anthocyanin after two hours at 70 °C and 60 per cent after two hours at 90 °C. At pH 7 it kept less than a third after half an hour, and the colour changed visibly.
- infusing — Boiled down with sugar the calyces make a syrup concentrate, which is diluted to drink. Mint or ginger is sometimes boiled with them.
- grinding — In Côte d’Ivoire the dried calyces are ground to a powder and used in sauces through the dry season.
The heating figures are from one laboratory, on an extract held in buffer and not on a sauce or a drink.
Storage and freshness
| Form | Good for | Conditions | Fridge |
|---|---|---|---|
| Dried flower | Not established | Cool, dark, dry and closed. | — |
Steep a few calyces in hot water. The water should turn clear red within a minute or two and taste sharply sour.
- A dull brown colour in place of dark red
- Mould or a musty smell
- Soil or grit
- Moisture uptake above the 12 per cent to which export calyces are dried
- Loss of the red anthocyanin colour
Quality is not the same as safety
Faded calyces are a matter of quality. Mouldy ones should be thrown away.
Forms
These forms differ enough to need separate answers: treating them as interchangeable produces a dish that is wrong.
Dried calyces
The whole dried calyx, dark red, sold loose or in sachets. It is boiled or steeped and strained out, or ground to a powder for sauces.
Sour and tart, colouring the liquid bright red.
Boil the dried calyces in water and strain. For a syrup the handbook gives one part dried calyces to four or five parts water, boiled down with a large amount of sugar and diluted to drink.
Ground dried calyces
The dried calyx ground to a powder. In Côte d’Ivoire it goes into sauces through the dry season; it is also the state in which laboratories extract and measure the calyx.
Stirred into a sauce, where the whole calyx would be boiled and strained out. The handbook records the use and gives no method.
Fresh calyces
The fleshy calyx as harvested, mostly water: 89 per cent in one Malaysian cultivar and 85 to 87 per cent in three Mexican varieties. Fresh calyces are cooked as a vegetable and in sauces in Africa, and the red lobes are chopped into fruit salads in the United States; most of the crop is dried.
Freshly harvested calyces are added to water-based sauces, often with oil, salt, onions, dried fish and hot pepper, and eaten with porridge or rice. Fresh green calyces are boiled with the leaves into a soup.
The water content is one Malaysian measurement of 89.4 per cent and a Mexican study’s figure of 85 to 87 per cent at harvest.
Botany
Hibiscus digitatus Cav. is listed as a synonym. The edible types belong to the cultivar group Sabdariffa; the tall fibre types, group Altissima, have a leathery, bristly calyx that is usually inedible.
Malvaceae
Chiefly the calyx, the cup of sepals at the base of the flower, which swells and turns fleshy around the fruit after flowering. The young shoots and leaves are a sour vegetable and condiment, and the seed is eaten roasted, ground or fermented.
A large annual herb, bushy and much branched in the edible types and 1.5–2 m tall, often red in stem, leaf stalk and calyx. The leaves are alternate and vary on one plant from undivided to deeply cut into three, five or seven lobes. Flowers sit singly in the leaf axils, pale yellow or pale pink and often dark red at the centre, and stay open for a few hours. After flowering the five-lobed calyx grows to as much as 5 cm, fleshy and dark red or purple, and closes round an ovoid capsule of 30–40 brown, kidney-shaped seeds. Some cultivars have no red pigment and bear pale green calyces.
Commonly confused with
Garden hibiscus
Hibiscus is a genus of 200–300 species, many of them grown as ornamentals. The hibiscus of herbal teas and of flor de jamaica is the calyx of this one species, not the petals of a garden shrub.
Sorrel
Roselle is called red sorrel, Jamaican sorrel and Indian sorrel in English and oseille de Guinée in French, for its sourness. The sorrel of European kitchens is a different plant altogether.
Kenaf and false roselle
Hibiscus cannabinus and Hibiscus acetosella. Their leaves can stand in for roselle leaves as a vegetable and, the handbook says, are sometimes sold together with them.
How it is grown
The plant, how it is propagated and farmed, what threatens the crop, and where it is produced now. Crop diseases here are plant health, not food safety.
Chiefly the calyx, which grows fleshy and red around the fruit after flowering and is picked before the capsule inside dries and splits. The young shoots and leaves are cut as a vegetable, and the seed is eaten roasted, ground or fermented.
From planting to first harvest: 4–6 months
An annual. Vegetative growth lasts four to six months, and leaves can be cut from six to eight weeks after sowing. Flowering begins when the days shorten, two to seven months after sowing; each flower is open for a few hours. The calyces are picked two to three weeks after flowering, and the fruit takes two to three months from pollination to ripen.
How it is propagated
- Seed.
Usually grown from seed, of which a thousand weigh about 15–28 g, broadcast or sown a few to a hole; some growers raise seedlings in a nursery and transplant them after about four weeks.
- Stem cuttings.
It can also be grown from stem cuttings.
Almost entirely self-pollinating, though some cross-pollination by insects may occur. The anthers shed their pollen shortly before the flower opens, and any movement of the flower carries it to the stigma.
Probably tropical Africa. Both handbook accounts say it may have been domesticated in Sudan about 6,000 years ago, first for its seed and later for its leaves and calyces; both hedge the date.
Wild relatives
- Hibiscus asper (Hibiscus asper Hook.f.) — Named by the South-East Asian handbook as one of the likely parents of roselle, which has twice its chromosome number; the other parent is not known.
Growing conditions
- Temperature · 18–35 °C
Grows between 18 and 35 °C. Growth stops at 14 °C and the plant dies after about 15 days at that temperature, or after two or three days at 10 °C. Flower and calyx production falls below 17 °C.
- Rainfall · 800–1600 mm
Thrives where 800–1,600 mm of rain falls through the year, and needs at least 100–150 mm a month while it is growing. Dry weather in the last months favours a good calyx crop; too much rain or humidity then lowers the quality of the calyces.
- Day length
Sensitive to day length. It flowers best when the day is shorter than twelve hours and needs about thirteen hours of light a day while growing, or it flowers too early. In Java it typically does not flower between December and March.
- Drought
Deep-rooted and fairly drought-resistant once established. Types with red pigment stand the Sahel better than the yellow-green ones.
- Soil
Grows on a wide range of soils, best on friable loams that hold moisture, and needs depth for its taproot. It tolerates both highly acid and moderately alkaline soils and does not tolerate waterlogging.
- Frost
Sensitive to frost, which is the main limit on growing it in temperate zones.
How it is farmed
- Smallholder farming · Sudan and the West African savanna
A rain-fed smallholder crop, sown at the start of the rains, often intercropped with pearl millet, sorghum, groundnut or cowpea or planted along field boundaries. In Sudan plots run from under a quarter of a hectare to two hectares. Farmers regard it as needing little input or labour: fertiliser is rarely applied and weeding is seldom done, though weeding raises the calyx yield.
- Home gardens
Grown in gardens as a leafy vegetable, or for leaves and calyces together, and watered by hand. In South-East Asia it is a typical home-garden plant.
- Agroforestry and shade systems · West Africa
Also grown in parkland systems under scattered trees such as the baobab, the African locust bean and the shea butter tree.
Most spices are grown in more than one way; none of these is the only one.
Harvest
Harvested by hand.
Calyces are picked two to three weeks after flowering, usually four to six months after sowing, before the fruit inside has dried and split.
Picked by hand, and picked repeatedly, since regular picking prolongs flowering. The calyces are then air-dried in the shade on plastic sheets, with good ventilation.
Fresh calyx yields are put at 4–6.5 t per hectare, or about 800–1,200 kg dried to 12 per cent moisture, and at up to 15 t fresh in Asia. Yields in Africa are much lower and more variable: Sudan reports an average of 93 kg of dry calyces per hectare, and the maximum in Senegal is 500 kg. The planted area in Sudan swung between 11,000 and 57,000 ha with rainfall and price. These are the handbook’s figures of 2011.
Where it comes from and how it is made
Probably tropical Africa. Both handbook accounts say it may have been domesticated in Sudan about 6,000 years ago, first for its seed and later for its leaves and calyces, and plants that appear to be truly wild have been collected in Ghana, Niger, Nigeria and Angola.
The date is the handbooks’ and is hedged in both; neither cites an excavation.
- Sudan (Kordofan and Darfur) — major producer. The main producer of dried calyces in tropical Africa, for local use and export, grown by smallholders. The planted area swung between 11,000 and 57,000 ha with rainfall and price.
- Senegal — notable producer. A major producer with Mali, almost all of it for domestic use and local markets.
- Thailand — major producer. Named with China and Mexico as a large-scale producer whose output shifted the market.
- China — major producer. A large-scale producer; its roselle sold for less than Egyptian and Sudanese in 1998.
- Mexico — notable producer. A review puts the harvested area at about 18,000 ha, some 85 per cent of it in Guerrero and Oaxaca.
- Egypt — notable producer. An exporter, with Jamaica.
The handbook account dates from 2011 and the review from 2020. They describe those years and are not a current ranking; no production statistic was read at source.
The calyces are picked by hand two to three weeks after flowering, usually four to six months after sowing and before the fruit inside has dried and split. Regular picking prolongs flowering. A single plant may give as many as 250 calyces.
- Picking — Calyces are picked by hand while still fleshy, before the capsule inside dries and opens.
- Drying in the shade — In most of Africa the calyces are air-dried, in the shade and with good ventilation, on plastic sheets laid on the ground.Why: Drying in full sun can lower the quality, and soil on the calyces lowers their value sharply.
- Packing — Dried calyces are sold loose in bulk or in small sachets across West Africa. In Senegal they are rolled into balls of 80 kg for export.
No grade scheme is described in the sources read. The handbook records that roselle exported to the United States and Germany must meet standards for moisture, acidity, residues and contamination, and that Sudanese roselle is regarded as of superior quality.
A smallholder crop, sown at the start of the rains and often intercropped with millet, sorghum, groundnut or cowpea, or planted along field boundaries. For calyces the plants are widely spaced, up to a metre apart. Farmers regard it as a crop that needs little input or labour: fertiliser is rarely applied in tropical Africa and weeding is seldom done.
A warm-climate crop that grows between 18 and 35 °C, stops growing at 14 °C and dies after a few days at 10 °C. It is sensitive to day length and flowers best when days are shorter than twelve hours. Deep-rooted and fairly drought-resistant, it does well with 800–1,600 mm of rain a year. Dry weather in the last months of growth favours a good calyx crop, and too much rain or humidity then lowers the quality of the calyces.
What processing and storage do to it, as measured
Drying · Depends on conditions furfural, 5-methyl-2-furfural, 2-acetylfuran, moisture, water activity, colour
Fresh calyces held 89.4 per cent water. Oven-drying and freeze-drying brought them to 8.9 to 9.6 per cent, at a water activity of 0.40 to 0.48; vacuum-drying left 12.9 per cent and sun-drying 15.6 per cent, at a water activity of 0.73. Every method changed the volatile compounds. Of 74 identified, the terpenes, several aldehydes and the fruity esters of the fresh calyx fell: the peak for linalool, the largest terpene of the fresh calyx, was less than a twentieth as large in every dried sample. Five of the six furans rose instead, furfural most of all, by between 36 and 111 times. The authors expect this to mean less of a fruity, floral and green smell and more of a caramel-like one. Ground vacuum-dried calyx stayed closest in colour to fresh, and its water extract was the nearest in lightness and redness to that of fresh calyx; the extracts of oven-dried, freeze-dried and sun-dried calyx were darker and less red. Under the electron microscope freeze-dried tissue looked most like fresh.
Conditions: in air · 50 °C in two ovens and under vacuum; below 45 °C in the sun; freeze-dried at −40 °C · 12 h in the ovens, 26 h under vacuum, 19 h in the sun, 48 h in the freeze dryer · Whole calyces of the Malaysian cultivar UMKL, dried in a single layer
The caramel-like note reported in dried roselle is, on this evidence, made in the drying and is not in the fresh calyx: the authors attribute the furans to sugars breaking down under heat at low water content.
What this does not show: One cultivar from one grower, with volatile compounds given as peak areas and not as amounts. The odour descriptions come from reference lists; no panel smelled the samples. The sun-drying was slowed by haze, the sun-dried calyces showed compounds the authors read as signs of fermentation, and they say those results should not be generalised. The fresh and vacuum-dried extracts were also the weakest, at 0.4 and 1.1 per cent soluble solids against 2.8 to 3.8, which bears on their lighter colour.
Measured on the spice
Drying · Depends on conditions Hibiscus acid, glucose, fructose, γ-aminobutyric acid, fumaric acid, moisture
Calyces from sixteen places were each dried two ways. The shade-dried lots averaged 10.5 per cent water and the tray-dried 7.9 per cent. Hibiscus acid was the main compound in a hot-water extract of every lot: 9.8 to 13.2 g per 100 g of dry powder after shade drying and 12.4 to 15.5 g after tray drying, about 12 g and 14 g on average, which the authors put as a loss of almost 15 per cent in the shade. Glucose and fructose were lower in most shade-dried lots too, at about 1.5 to 2.3 g per 100 g each against 2.0 to 2.7 g, while γ-aminobutyric acid and fumaric acid were higher. The authors suggest why: calyces that dry slowly stay damp and warm for days and may begin to ferment. Four of the sixteen shade-dried lots did not show the pattern, which the authors put down to how the drying went and not to where the plants grew.
Conditions: in air · 26–28 °C in the shade; 60 °C in the tray drier · Four days in the shade; six hours in the tray drier · About 50 g of fresh red calyces from each of sixteen places, fifteen in the Garo Hills of Meghalaya and one at Noida
It does not overturn the handbook’s advice for Africa, which is to dry in the shade because full sun lowers quality. The handbook sets shade against sun; this study set shade against a heated tray at 60 °C, above the 43 °C the handbook gives as the limit for heated dryers, and measured acids and sugars, not colour.
What this does not show: One study, on about 50 g of calyces per lot. The compounds were measured in a five-minute hot-water extract brought to neutral pH, not in the calyx itself, and citric and malic acids were not among those the study assigned. Colour and anthocyanins were not measured. The abstract says all sixteen lots came from Meghalaya; the table of locations places one at Noida, in Uttar Pradesh.
Measured on the spice
Drying · Depends on conditions Malic acid, Citric acid, Anthocyanins, succinic acid, tartaric acid, oxalic acid, colour
Five acids were measured by liquid chromatography in a water extract of the ground calyx. In freeze-dried calyces succinic acid was the largest, at 246 to 325 mg per 100 g of dry weight, then malic at 122 to 153 mg, tartaric at 48 to 60 mg, citric at 7 to 10 mg and oxalic at 1 to 10 mg, about 0.44 to 0.52 g in all. Six days of drying in the sun cut the total by 45 per cent in two varieties and 55 per cent in the third; malic and succinic acid fell most, and citric acid did not fall, standing at 22 to 27 mg. Drying in hot air changed the totals little: they ran from 0.36 to 0.61 g per 100 g across the three temperatures and varieties, and the 70 °C lots were as high as the freeze-dried ones or higher. The acidity of the water extract, by titration, was 37 to 44 per cent lower from sun-dried calyces than from fresh ones. In the two red varieties the sun-dried calyces also gave about 37 per cent less anthocyanin on average, and their extracts were darker.
Conditions: in air · In the sun on concrete; in a tray drier at 50, 60 and 70 °C · Six days in the sun, from nine to five, prolonged by cloud and rain; six to eight hours in the drier · About 10 kg of fresh calyces per lot of three Mexican varieties grown at Acaponeta, Nayarit: Negra Quiviquinta, dark red; UAN-9, light red; UAN-16, white
The authors put the loss in the sun down to its length: calyces lying damp for six days may have had their acids partly fermented by the organisms on them, where hot air at 50 °C or more dries them in hours. It agrees with the handbook’s caution that drying in the sun can lower quality, and with the Indian study in which slow drying in the shade cost hibiscus acid. Of the methods tried, the authors judged hot air at 70 °C to keep the calyx best.
What this does not show: One harvest of three varieties at one site, with sun-drying that took six days because of cloud where two or three are usual; the authors cite another Mexican study that found no loss of acidity after three days in the sun. Hibiscus acid was not measured, so the five acids add up to about half a gram per 100 g where another study found ten grams or more of hibiscus acid alone. The conclusion gives the average loss of acids in the sun as 49.9 per cent, which is not the mean of the three figures in the text.
Measured on the spice
Fermentation
Bikalga
Alkaline fermentation · Burkina Faso · also fermented roselle seed condiment
The seeds of roselle, Hibiscus sabdariffa, the plant whose calyx is dried for drinks. The studies read call bikalga an alkaline fermented food used as a condiment in Burkina Faso, and one says it is widely eaten there and in neighbouring countries.
Seventy bacteria isolated by culture from bikalga made in different regions of Burkina Faso were identified by DNA typing and sequencing. Bacillus subtilis was the commonest, at 42 of the 70, followed by Bacillus licheniformis at 16; the others were B. cereus, B. pumilus, B. badius, Brevibacillus bortelensis, B. sphaericus and B. fusiformis, as the abstract abbreviates them. A later study describes the fermentation as dominated by species of the Bacillus subtilis group. Lactic acid bacteria are present too: Enterococcus faecium, Enterococcus hirae and Pediococcus acidilactici were isolated from bikalga and soumbala. The authors propose selecting starter cultures; none of the abstracts reports one in use.
A study of how it is made at production sites in Burkina Faso lists the main steps as cleaning the seeds, cooking them with an alkaline liquid drawn from ash, fermenting, steaming and drying. The pH rose with cooking and fermentation, to 8 or 9, and then fell with steaming and drying, in some cases to 6. The seeds studied held 28.69 per cent crude protein and 26.39 per cent carbohydrate before and 26.47 and 13.7 per cent after, with moisture, ash and titratable acidity higher in the fermented seed.
Used as a condiment. The abstracts read say no more than that about how it is cooked with.
Forty-one Bacillus isolates from soumbala and bikalga were screened for toxins. All nine Bacillus cereus among them produced enterotoxin when grown in fermenting African locust bean, and no isolate of another species did; the gene fragment specific to producers of the emetic toxin was not detected in any isolate. The test fermentation was of locust bean, not of roselle seed. In a separate laboratory study, liquid from cultures of three Bacillus subtilis strains isolated from bikalga inhibited Listeria monocytogenes, Staphylococcus aureus and Bacillus cereus; that was shown in culture and not in the condiment.
What goes into it
- Fermented: Roselle seeds (The seed of the plant, not the calyx the catalogue chiefly describes.)
- Carrier or binder: Ash leachate (An alkaline liquid drawn from ash, added when the seeds are cooked. It is neither a seasoning nor a culture; the abstract calls it alkalinising.)
Organisms studies found, and how
- Lactic acid bacteria: Pediococcus acidilactici — detected, grown in culture. Isolated from bikalga and soumbala taken together, with Enterococcus faecium and Enterococcus hirae. Sources: Genotypic diversity of lactic acid bacteria… (Abstract)
- Bacillus and its relatives: Bacillus subtilis — reported as dominant, grown in culture. Forty-two of 70 isolates from bikalga made in different regions of Burkina Faso. Sources: Identification of Bacillus spp. from Bikalg… (Abstract) Bacillus licheniformis — detected, grown in culture. Sixteen of the same 70 isolates. Sources: Identification of Bacillus spp. from Bikalg… (Abstract) Bacillus cereus — detected, grown in culture. Among the same 70 isolates; the abstract does not give its number. Sources: Identification of Bacillus spp. from Bikalg… (Abstract)
What is not established: All five studies were read in the abstract only; the fuller texts could not be reached. The steps and the acidity come from one abstract, which does not say how many sites it studied, how long the fermentation lasts or at what temperature. Nothing read measures ammonia, aroma compounds or free amino acids, so no compound is recorded as changing. The toxin study pooled isolates from bikalga and soumbala and does not say how many came from each. The handbook account of roselle records a cake of fermented seed in the Plateau region of Nigeria; whether that is the same kind of product is not said.
Buying and quality
Buy the whole dried calyx. It can be boiled and strained for a drink or ground when a powder is wanted for a sauce.
- Whole, dark red calyces, dry and free of soil and grit.
- Sold as hibiscus, flor de jamaica, sorrel, karkade or bissap; all are the same calyx.
- No mould and no musty smell.
Physical properties and standards
Moisture, water activity, ash, volatile oil and the like — what standards require kept apart from what has been measured.
| Property | Value | Sample and method |
|---|---|---|
| Moisture (fresh) | 89.4 % | Fully mature calyces of the cultivar UMKL from a grower at Kepala Batas, Malaysia; the handbook account of the crop quotes 86.2 g per 100 g from a food composition table · Water content of fresh calyces by the air-oven method at 105 °C |
| Moisture (dried flower) | 8.9–15.6 % | One Malaysian cultivar, UMKL, dried whole in a single layer · Water content of calyces after five drying treatments: 8.9 to 9.6 per cent from two ovens and a freeze dryer, 12.9 from vacuum-drying, 15.6 from sun-drying slowed by haze |
| Water activity (dried flower) | 0.4–0.73 aw | One Malaysian cultivar, UMKL, dried whole in a single layer · Water activity at 25 °C after five drying treatments: 0.395 to 0.482 from ovens and freeze dryer, 0.605 from vacuum-drying, 0.727 from sun-drying slowed by haze |
| Moisture (dried flower) | 3–15.2 % | Red calyces from fifteen places in the Garo Hills of Meghalaya and one at Noida, dried in the shade for four days or in a tray drier at 60 °C for six hours · Water content of sixteen lots dried two ways, by oven at 105 °C: shade-dried 5.9 to 15.2 per cent, averaging 10.5; tray-dried 3.0 to 15.0 per cent, averaging 7.9 |
| Characteristic compound (dried flower) | 9.8–15.5 g/100 g dry powder | Thirty-two lots: red calyces from sixteen places in India, each dried in the shade and in a tray drier · Hibiscus acid by quantitative NMR in a five-minute hot-water extract of the powdered calyx: 9.8 to 13.2 g in shade-dried lots and 12.4 to 15.5 g in tray-dried ones |
A limit is set by a rule of one kind, in one place; a measurement describes particular samples. Neither is a property of every jar.
History and trade
The handbooks treat roselle as an old African crop, perhaps domesticated in Sudan some 6,000 years ago, and taken up first for its seed and then for its leaves and calyces. Vegetable types reached India and the Americas in the seventeenth century. Its use as a fibre plant is much later: seed sent from Ghana to the Philippines in 1914 began it, and Java, Malaysia, Sri Lanka and India followed within a few years.
A handbook’s summary of the literature. No excavation report or early text was read.
About 4000 BC · Sudan
Roselle may have been domesticated in Sudan, first for its seed. Both handbooks give the date and both hedge it.
An approximate date from the handbooks, not from an excavation report.
Seventeenth century
Vegetable types of roselle were introduced to India and the Americas.
The handbooks give the century and no year.
1914 · The Philippines
Seed of the fibre type was received in the Philippines from Ghana; the type was unknown outside Africa until then.
The handbook of 2011 says trade in the calyces had risen steadily, with 15,000 t a year entering the world market and Germany and the United States the large importers. In 1998 importers there paid US$1,200–1,700 a tonne for Egyptian and Sudanese roselle and less for Chinese; in 2003 poor quality in Thailand and China after heavy rain sent prices to US$4,000 a tonne. The dried calyces are used in Western countries as a base for herbal teas and as a source of red food colour.
Figures of the handbook’s period. The same account gives a much larger export figure for Sudan alone in 1995, which does not sit easily with its world total, so it is not repeated here.
Claims we do not accept at face value
“Roselle is native to India and Malaysia.”
popular but unsupported
Stated in a pharmacological review read for this profile and in much writing about hibiscus tea. Both handbook accounts place its origin in tropical Africa, record apparently wild plants from Ghana, Niger, Nigeria and Angola, and date its arrival in India to the seventeenth century.
Culture
Recorded by tradition rather than merged into one narrative — these are genuinely different practices.
Garo Hills, north-east India
A home-garden vegetable in the Garo Hills of Meghalaya, where it is called Gal˙da. A survey of the hills records roselle and kenaf together: the leaves and calyx are eaten, fresh leaves are cooked with dried fish, dried leaves are cooked with pounded rice powder and pork, and pickles are made. It lists three dishes, Gal˙da na˙kam, Gal˙da gisi pura and Gal˙da wak, names the first among the foods that are part of the daily diet there, and records a roselle pickle among the products local makers sell.
- Leaves cooked with dried fish
- Roselle pickle
Sudan, Egypt and North Africa
The dried red calyces are made into a tea, karkade, drunk hot or more often cold with sugar. The handbook calls the drink very popular from Senegal to Sudan and in Egypt and the other countries of northern Africa.
- Karkade, hot or cold
Senegal and the West African savanna
The juice is sold chilled or frozen along roads and in town markets, as bissap in Senegal and da bilenni in Côte d’Ivoire, Mali and Burkina Faso, sometimes with mint or ginger boiled in. The plant is also a kitchen ingredient: leaves and calyces are cut fine into water-based sauces with oil, onion, dried fish and chilli, eaten with porridge or rice; in Senegal the stewed green calyces are a condiment, bëkëj, for rice dishes; and in Côte d’Ivoire the powdered dried calyx goes into sauces in the dry season.
- Bissap and da bilenni
- Bëkëj with rice
- Powdered calyx in sauces
Nigeria
In the Plateau region the seeds are fermented into a cake eaten as “sorrel meat”. A review names zoborodo as the drink made in Nigeria by boiling the calyces with sugar.
- Fermented seed cake
- Zoborodo
Burkina Faso
The seed, not the calyx, is the seasoning here: it is fermented into bikalga, a condiment that microbiologists class with the alkaline ferments of locust bean and describe as widely eaten in Burkina Faso and neighbouring countries.
- Bikalga, fermented roselle seed
Mexico
The dried calyx is jamaica, and the drink made from it jamaica water. A review puts some 85 per cent of the Mexican crop in the states of Guerrero and Oaxaca.
- Agua de jamaica
South-East Asia
A home-garden plant. The young shoots and leaves are eaten raw or cooked as a vegetable or condiment, sour and slightly mucilaginous, and the calyces are made into syrup, jam and jelly.
- Sour leaves as a vegetable or condiment
What it is called
- English: roselle, red sorrel, Jamaican sorrel, hibiscus
- Arabic: karkade
What we do not know
Published openly. A gap we have named is more useful than a gap we have filled with plausible prose.
Not yet established for roselle:
- Archaeological evidence
- Ceremonial use
- Traditional medicinal context
- Regulatory limits
- Traditional uses