Shogaol
Also written 6-shogaol, [6]-shogaol
Quick answer
The pungent compound that gingerol becomes when ginger is dried or heated, and the reason dried ground ginger is sharper, hotter and less fresh than the root it came from.
What it does
Shogaol is markedly more pungent than the gingerol it forms from, and the heat it gives is harsher and sits further back in the throat. Fresh ginger contains very little; dried ginger contains a great deal, because drying and storage dehydrate gingerol into shogaol. That single reaction is why the two forms are not interchangeable at any ratio: a recipe asking for fresh ginger and given ground ginger gets a hotter, flatter, more peppery result with none of the bright citrus top note, and no quantity adjustment fixes both at once.
How it behaves when cooked
Four properties of the molecule, and what they mean at the stove.
- Volatility
- low
- Fat solubility
- high
- Water solubility
- low
- Heat stability
- high
Shogaol is not volatile and survives cooking, so the heat of dried ginger lasts through a long bake or braise in a way that the fresh root’s aroma does not. It is fat-soluble, which is why ground ginger works in a butter-rich biscuit dough and why its heat builds in an oily curry. The practical rule follows from where it comes from: use dried ginger where sustained warmth is the point — gingerbread, spice cakes, long-cooked meat — and fresh ginger where brightness is, added late. Heating fresh ginger for a long time moves it part of the way towards dried, which is one reason a slow-cooked ginger dish tastes warmer and less zesty than one where the ginger went in at the end.
Not present until the plant is damaged
Gingerol
Not formed by damage but by heat and time: gingerol loses a molecule of water — a dehydration of its β-hydroxy ketone — during drying, storage and cooking. The conversion is faster at higher temperatures, which is why the drying method changes the pungency of the finished spice.
Spices that carry it
Recorded on the compound rather than on each spice, so the two cannot disagree.
Formed on drying, from gingerol. Minor in the fresh rhizome and a principal pungent compound of dried ginger — the clearest case in the catalogue of one spice holding two different pungencies depending on its form.
What cooking and processing were measured to do to it
Findings from studies in which this compound was followed through heat, fat, water, drying or storage. Each belongs to its study and its conditions.
Toasting and dry roasting · Converts Gingerol, Shogaol
Fresh ginger from one Korean farm held 6200 mg of 6-gingerol per kilogram of dry weight and only 29 mg of 6-shogaol. Dry heat in a convection oven moved gingerol towards shogaol, faster as the temperature rose from 100 to 130 °C. After 360 min at 130 °C the 6-gingerol in sliced fresh ginger had fallen from 6243 to 2877 mg/kg while 6-shogaol had risen to about 1350 mg/kg; the paper gives 1161 mg/kg for the same sample in a later passage.
Conditions: in air · 100, 110, 120 and 130 °C in a convection oven · 10 to 360 min · Fresh ginger in 5 mm slices and freeze-dried ginger powder, from one farm
Heat alone, without any drying step beforehand, shifts ginger from gingerol towards shogaol, but in this study the shift took hours at oven temperatures above the boiling point of water. A few minutes in a pan is a far smaller treatment than anything measured here.
What this does not show: One farm, one harvest and a laboratory oven, with heating times of up to six hours. The paper reports two different shogaol figures for the same sample. It measured the pungent compounds only, not taste, and did not measure zingerone.
Measured on the spice
Toasting and dry roasting · Converts Gingerol, Shogaol
Under the same dry heat, dried ginger powder converted more of its gingerol than sliced fresh ginger did. After 360 min at 130 °C the powder went from 6288 to 2265 mg of 6-gingerol per kilogram and reached 1611 mg/kg of 6-shogaol, significantly more than the slices. The authors attribute the difference to the energy the fresh slices spend evaporating their water before they can heat up.
Conditions: in air · 130 °C in a convection oven · 360 min · Freeze-dried ginger powder compared with 5 mm slices of fresh ginger
What this does not show: The powder was freeze-dried in the laboratory so that it began with almost no shogaol; commercially dried ginger already contains some. The explanation offered for the difference was proposed by the authors, not tested.
Measured on the spice
Steaming · Converts Gingerol, Shogaol
Moist heat converted gingerol to shogaol far more effectively than dry heat at the same temperature. After 360 min in an autoclave the 6-gingerol in sliced fresh ginger had fallen from 6258 mg/kg of dry weight to 4436 mg/kg at 100 °C, 2840 at 110 °C, 746 at 120 °C and 571 at 130 °C. The highest 6-shogaol content in the study, 2991 mg/kg, came from 360 min of moist heat at 120 °C, roughly twice what dry heat produced in the same slices.
Conditions: in steam · 100, 110, 120 and 130 °C in an autoclave · 10 to 360 min · Sliced fresh ginger under pressurised moist heat
At 100 °C, the temperature of a simmering pot, six hours of moist heat still left about seven tenths of the 6-gingerol in place. The large conversions in this study belong to pressurised heat above the boiling point.
What this does not show: An autoclave, not a pot: the ginger was heated in pressurised steam, not simmered in liquid, so nothing could leach out. One farm and one harvest. Zingerone was not measured.
Measured on the spice
Steaming · Depends on conditions Shogaol
Shogaol did not accumulate without limit. Under moist heat at 130 °C, 6-shogaol rose to a maximum of 2890 mg/kg of dry weight at 240 min and then fell with further heating; under dry heat at 130 °C the powder likewise peaked at 240 min and declined slightly afterwards. At 120 °C, by contrast, shogaol was still rising at the end of the 360 min tested.
Conditions: in steam · 130 °C · Up to 360 min; the peak came at 240 min
What this does not show: The study did not identify what the shogaol became once it began to fall. The times involved are far longer than cooking times.
Measured on the spice
Simmering and boiling · Converts Gingerol, Shogaol
In water, [6]-gingerol loses a molecule of water to give [6]-shogaol, and the reaction runs both ways: shogaol takes water back up to re-form gingerol until the two reach a balance. The rate depended on acidity, with gingerol most stable at pH 4. At 100 °C and pH 1 the reaction was relatively fast and reached equilibrium within 2 h. Shogaol was the major degradation product.
Conditions: in water · 37 to 100 °C · pH 1, 4 and 7 · Pure [6]-gingerol in aqueous solution, followed by HPLC
What this does not show: Read in the abstract only. A solution of the pure compound, studied for pharmaceutical purposes; pH 1 is far more acid than any food. The abstract gives no rate constants and does not report zingerone.
Measured on the pure compound
Drying · Converts Gingerol, Shogaol, pungency
Ginger dried in the open sun held more 6-, 8- and 10-gingerol than ginger dried in a solar tunnel or a hot oven, and less of the corresponding shogaols. Raising the oven temperature from 120 to 150 °C increased the shogaols sharply; at 180 °C both gingerols and shogaols fell, which the authors attribute to degradation and polymerisation. At 150 °C the shogaol content rose with drying time up to 6 h and dropped at 7 h. The order of shogaol formation was oven at 150 °C, then solar tunnel, then open sun.
Conditions: in air · Open sun at 23 to 34 °C; solar tunnel at 31 to 47 °C; oven at 120, 150 and 180 °C · Nine days in the sun; up to 7 h in the oven · Sliced rhizomes dried to about 10 per cent moisture
What this does not show: The oven temperatures are far above those used to dry ginger for the spice trade, so the oven results show the direction of the chemistry and not a commercial product. The values sit in a table and figures; the text read gives the comparisons and not every number. One source of rhizomes.
Measured on the spice
Drying · Depends on conditions Gingerol, Shogaol, volatile oil
Ginger powder of the variety Xiaolin Huangjiang dried in two stages, 90 min at 120 °C followed by 150 min at 80 °C, held 11.87 mg/g of the gingerol group measured (6-, 8- and 10-gingerol and 6-shogaol), against 7.12 mg/g after 360 min at a constant 80 °C. The slower constant drying kept far more volatile oil: 3.46 per cent against 1.29 per cent.
Conditions: in air · 120 °C then 80 °C, against a constant 80 °C · 90 min plus 150 min, against 360 min
A drying schedule that keeps ginger’s pungent compounds is not necessarily the one that keeps its aroma; in this comparison the two pulled in opposite directions.
What this does not show: Read in the abstract only. The figures given are for one of three varieties, and the abstract does not separate gingerols from shogaol in the total.
Measured on the spice
Not to be confused with
Compounds a reader is likely to take for this one, and why they differ.
Gingerol
Its precursor, and the pungency of fresh ginger. The two are often written together as "gingerols and shogaols"; they are different molecules with different heat, and which one dominates is the difference between fresh and dried ginger.
Capsaicin
Both act on the same heat receptor, TRPV1, which is why ginger and chilli are both described as hot. Capsaicin is far more potent and lingers; shogaol’s heat is sharper and shorter.
Questions this page answers
- what is shogaol
- shogaol vs gingerol
- why is dried ginger hotter than fresh
- what is 6-shogaol