Material guide: ethyl maltol — the solubility field unusually gives four actual percentages

Short version: a molecule that does not exist in nature, rated at four to six times maltol's potency, and whose most useful property is that the database filled in actual solubility numbers for it. That is a minority in this database.

The fields

Field	Value
CAS	4940-11-8
Head synonym	3-hydroxy-2-ethyl-4H-pyran-4-one
Formula	C7H8O3, MW 140.14
Database category	Flavor enhancers, flavoring agents
Appearance	White crystalline powder (est)
Melting point	89–93 °C
Boiling point	289–290 °C @ 760 mmHg
Flash point	> 93.33 °C
logP	0.80 (est)
Solubility	Alcohol 12%; benzyl alcohol 10%; phenethyl alcohol 5%; propylene glycol 5.5%; water 24,230 mg/L (est)
Odour type	Caramellic
Odour	Sweet, caramellic, jammy, strawberry, cotton candy, berry, sugar
Strength	High; evaluation recommended at 5% solution or less (rank 3)
Substantivity	360 hours at 20% in benzyl alcohol
Shelf life	24 months
Natural occurrence	Not found in nature
Suppliers	75
Regulatory	JECFA 1481, FEMA GRAS 3487, CoE 692, FLAVIS 07.047
GHS	H302 harmful if swallowed
Oral toxicity	Rat LD50 1,150 mg/kg, mouse 780 mg/kg
Dermal toxicity	Rabbit LD50 > 5,000 mg/kg

Its solubility field has numbers

This is the most useful thing about the material, and a minority case in the database.

This series has measured it: of 42,225 records, 23,941 (56.7%) have a solubility field, but most only list solvent names without quantities. Ethyl maltol gives four.

alcohol, 12%; benzyl alcohol, 10%; phenethyl alcohol 5%; propylene glycol, 5.5%

Alcohol at 12%. That single number settles an entire forum argument. This round's beginner article analyses a 39-reply thread in which someone writes that they have "a 10% dilution in 99.5% alcohol that's been stable with no crystalizing for months". Ten per cent is under the 12% ceiling, so it stays stable.

And in the same thread, someone tried maltol at 10%, 5% and 2.5% and only 1% worked. That is a different molecule.

The difference from maltol is melting point

	Ethyl maltol	Maltol
CAS	4940-11-8	118-71-8
Melting point	89–93 °C	159–162 °C
logP	0.80	0.40
Alcohol solubility	12%	listed, no figure
Propylene glycol	5.5%	2.8%
Glycerin	—	1.2%
Water	2.42% (est)	1.09% (exp @15 °C)
Natural occurrence	Not found in nature	Cocoa, coffee, roasted malt, raspberry…
Suppliers	75	107

Seventy degrees apart.

This round's beginner article works it out with Yalkowsky's General Solubility Equation (log S = 0.5 − 0.01(melting point − 25) − logP): the predicted water solubility ratio is 2.19×, against 2.22× from the database's own numbers.

Decomposed, melting point alone accounts for 4.95× of that 2.19, while logP pulls 0.40× the other way (ethyl maltol is the more lipophilic, and that term works against it). Reason from polarity alone and you get the direction wrong.

Chu and Yalkowsky's 2009 abstract puts it in one line: "log P alone is only half of the solution, and there is a need to include the melting point when dealing with crystalline solutes."

"4-6 x"

The notes field reads:

"Flavour enhancer and flavouring agent, sweetener, 4-6 x potency of 3-Hydroxy-2-methyl-4H-pyran-4-one"

That chemical name is maltol. So the database rates ethyl maltol at four to six times maltol's potency.

Note the context of that sentence: it appears in a flavour description, about sweetness enhancement, not odour strength. Both materials' odour strength fields read "high, evaluation recommended at 5% or less", both at rank 3. So the "4-6 x" belongs to the taste side and cannot be used as an olfactory conversion factor.

The odour fields do differ, though:

	Odour
Ethyl maltol	Sweet, caramellic, jammy, strawberry, cotton candy, berry, sugar
Maltol	Sweet, caramellic, cotton candy, jammy, fruity, baked bread, burnt

Ethyl maltol has strawberry; maltol has baked bread and burnt. Mosciano's 1991 description in Perfumer & Flavorist is "sweet sugary, caramellic, jammy, strawberry-like", and another supplier record says "candy-floss / cotton".

Not a strong and a weak version of one thing, but two molecules with different centres of gravity.

Not found in nature

The natural occurrence field: not found in nature.

Worth setting beside maltol's, which lists fir, chicory, cocoa, coffee, buckwheat honey, roasted malt, bell pepper, larch bark, raspberry and wild strawberry — over a dozen sources.

Maltol is a product of roasting; ethyl maltol is manufactured.

That bears directly on natural claims. Ethyl maltol smells sweeter, more strawberry-like and more immediately likeable, and dissolves far better. It is more convenient on every practical axis, and the price is that it does not exist in nature.

(The database's natural_synthetic field reads natural/synthetic for both, which contradicts ethyl maltol's natural occurrence field saying "not found in nature". This series flags database contradictions plainly rather than resolving them. I go with the natural occurrence field here, being the more specific one.)

Substantivity 360 hours

The substantivity field reads 360 hours at 20% in benzyl alcohol.

Two things about it:

1. It was measured in a 20% benzyl alcohol solution, not neat. This series has met the same style of annotation before (sotolon's was "3% in propylene glycol"). Different measurement conditions cannot be compared with each other.
2. 360 hours is fifteen days. That is long for a sweet material. Maltol is 372 hours under the same conditions, so the two are close.

It does not leave early. An advantage in gourmand work and a problem when you have overdosed it.

In the corpus

Across 954 published formulas, the maltols (both molecules, all spellings) appear in 43 (4.5%) — 22 with ethyl maltol, 22 with maltol, some formulas using both, at a median share around 1% in each case.

This series computed gourmand genre enrichment in article #46 while analysing a crème brûlée formula, and deleted those ratios because the genre held only 12 formulas. The same restraint applies here: no genre statistics.

What can be stated is the absolute count, and that the French crème brûlée formula in article #46 used ethyl maltol at 30 parts out of 1000.

Whether to use it

• For caramel, cotton candy and strawberry directions it is far easier to work with than maltol. Twelve per cent in alcohol against maltol's low single digits is a wide gap.
• Evaluate from a 5% dilution. The database recommends 5% or less, at strength rank 3.
• It is a solid (white crystalline powder, melting at 89–93 °C). Have a spatula and weighing boats; it will not melt on its own in summer.
• Twelve per cent is a ceiling, not a recommendation. Dilutions near the ceiling risk precipitating on cooling, which this series covers in articles #49 and #51. Leave headroom.
• It cannot go into a natural-claim product. Not found in nature, whereas maltol can.
• Its oral toxicity is higher than maltol's (rat LD50 1,150 mg/kg). That does not bear on topical use, but it is part of why the two are assessed separately in food regulation.

What this doesn't establish

• The four percentages in the solubility field carry no temperature. Solubility varies with temperature and this field does not say at what temperature it was measured — the key piece of information for "will my 12% precipitate in winter", and it is missing.
• "4-6 x potency" is a flavour statement, not an olfactory one. Both materials share an odour strength rank, and that factor cannot be used to convert doses.
• The 360-hour substantivity was measured at 20% in benzyl alcohol and cannot be compared directly with other materials' "at 100%" figures.
• The natural_synthetic field contradicts the natural occurrence field. I follow the latter without resolving the former.
• The GSE calculation lives in this round's beginner article and predicts water solubility, not alcohol solubility. The relative difficulty should point the same way in ethanol, but the factor will not be the same.
• Both cited papers measured drugs, not fragrance materials. What is cited is the model and its melting point coefficient.
• I have not smelled it and have run no solubility tests. The whole piece rests on database fields and forum reports.