Compound
4-Vinylguaiacol
The clove compound produced by any yeast carrying a ferulic acid decarboxylase, which gives a spicy character without any Brettanomyces being involved.
Also called 4-VG.
- Class
- Phenolics
- Formula
- C9H10O2
- How often it matters
- Occasional
What it does in cider
- Forms in one step from ferulic acid, so it needs only a decarboxylase rather than the full two-enzyme sequence.
- Is produced by a wide range of yeasts, including some Saccharomyces strains and many wild species, making it far more common in spontaneous ferments than the ethylphenols.
- Contributes a clove and spice note that some styles value and that reads as a fault in a cider aiming at clean fruit.
- Serves as the substrate that Dekkera reduces to 4-ethylguaiacol, so its presence in a cider carrying Dekkera is temporary.
How it is perceived
What the compound registers as, and at roughly what concentration. Perception is not a property of the molecule alone: sugar, tannin and carbonation all change where a threshold falls.
- clove
- spice
- smoky
- medicinal
Perceptible in the tens to hundreds of micrograms per litre depending on what else is present; more readily noticed in a light, low-tannin cider than in a phenolic one.
Descriptors it is responsible for
Sensory records that name 4-Vinylguaiacol as a cause. Each states the perception and the mechanism behind it.
- Clove — The clove note of 4-vinylguaiacol, formed when yeast decarboxylates ferulic acid from the fruit’s own phenolics.
- Smoky — A wood-smoke note from 4-ethylguaiacol, the guaiacyl counterpart of the ethylphenol pathway.
- Apple pie — Cooked apple carrying a spice layer — clove, cinnamon or nutmeg — from added spice, from wood, or from yeast-derived vinylguaiacol.
- Cinnamon — Warm sweet-spice character from cinnamaldehyde in added spice, or from oak-derived compounds in a barrel-aged cider.
The structure it moves
| Dimension | What it is |
|---|---|
| Phenolic character | Smoky, spicy, leathery or medicinal aromas that sit apart from fruit. |
| Fermentation character | Aromas made by the ferment rather than carried in from the fruit. |
What forms it
Processes that put this compound into the drink, or increase how much of it is there.
Wild fermentation
Letting the microflora already present on the fruit and in the press house carry the ferment, in a succession rather than as a single organism.
Inoculated fermentation
Starting a ferment by pitching a chosen yeast culture so that one known strain, rather than the fruit’s resident population, does the work.
Yeast selection
Choosing which cultured strain to pitch, on the basis of the temperature, nitrogen, alcohol and aroma behaviour that separates one commercial yeast from another.
Juice pasteurisation
Heat treatment of juice before fermentation, which inactivates enzymes and microorganisms, and in doing so removes the wild flora that would otherwise ferment it.
What removes or limits it
Processes that reduce it, hold it below a threshold, or stop it forming in the first place.
Barrel ageing
Holding cider in wood — which may mean an old neutral vat used simply as a vessel, or fresh or spirit-seasoned oak used as a source of flavour, and the two are not the same operation.
Fining
Adding a reactive agent that binds a target colloid and carries it to the bottom, chosen according to whether the problem is tannin, protein or a phenolic taste fault.
Faults it is implicated in
Being implicated is not the same as being a fault. Several of the compounds on this site are ordinary constituents of a sound cider and define a named fault only above a concentration.
Organisms that produce it
Which organism is responsible usually decides whether the compound is a feature or a symptom.
Dekkera bruxellensis
The yeast behind 4-ethylphenol, and the organism that a cider tradition may regard as its signature or its ruin depending on where and how it is made.
Saccharomyces cerevisiae
The yeast that finishes essentially every cider, whether it arrives in a sachet or from the fruit, the press and the vessel.
Wickerhamomyces anomalus
A tolerant, ester-heavy yeast common in fruit and juice, notable both as a producer of ethyl acetate and as a source of antimicrobial killer toxins.
Pichia membranifaciens
A film-forming yeast that grows as a skin on the surface of cider left in contact with air, consuming ethanol and acid and leaving the cider thin.
About 4-Vinylguaiacol
The ability to decarboxylate hydroxycinnamic acids is widespread. Many wild yeasts have it, and so do some cultured Saccharomyces strains — the trait brewers call POF, for phenolic off-flavour, and select for or against depending on the beer. In cider it means that a clove-like spicy note can appear in a ferment with no Dekkera anywhere near it, purely from ferulic acid being decarboxylated to 4-vinylguaiacol.
This matters diagnostically. A phenolic character that is clove-like and appeared during fermentation is probably vinylguaiacol from the primary yeast population; one that is leathery and appeared slowly during barrel maturation is probably ethylphenol from Dekkera. The remedies are quite different, and mistaking one for the other leads a producer to sanitise a cellar that was not the problem.
Heat also generates it. Ferulic acid decarboxylates thermally, so pasteurised juice and heat-concentrated products can carry a clove note that no organism produced. Where a cooked character in a heat-treated cider is described as spicy, this is often what is being smelled.
Related compounds
Compounds it is formed from, converted into, confused with, or routinely met alongside.
Phenolics
4-Ethylguaiacol
The smoky, clove-like partner of 4-ethylphenol, made by the same organisms from ferulic acid, and the compound that pushes phenolic character from medicinal towards spicy.
Phenolics
4-Ethylphenol
The horse-and-sticking-plaster compound, made by *Dekkera* from a phenolic acid the fruit supplied, and the clearest case in cider of one molecule being a tradition in one glass and a fault in another.
Phenolics
Hydroxycinnamic acids
The family of small phenolic acids that browns a juice, and whose release from their esters supplies the raw material for every volatile phenol a cider can develop.
Phenolics
Eugenol
The clove compound of oak and of actual cloves, arriving in cider from wood contact or from deliberate spicing rather than from the fruit.
What people ask next
Questions readers ask about the things this page mentions. Each one goes to the section that answers it rather than to a page written to receive the question.
- Which yeast ferments cider — Saccharomyces cerevisiae finishes almost every cider fermentation, whether it was pitched or arrived from the press house. In a spontaneous ferment it is not the first organism present, only the one that survives the alcohol it makes.
- How does cider ferment — Yeast consumes the sugar in apple juice and produces roughly equal masses of ethanol and carbon dioxide, along with the esters and higher alcohols that give cider much of its aroma. In a wild ferment several yeast species take turns before *Saccharomyces* finishes the job.
- Is cider vegan — Cider itself is a plant product, but some producers clarify it with animal-derived finings such as gelatine, isinglass or chitosan. Vegan status therefore depends on the fining regime, which is why some ciders are certified and others are not.
- What yeast should i use for cider — CiderHQ does not recommend brands. The choice is between a neutral, reliable strain that lets the fruit show, an aromatic wine strain that adds its own esters, and no addition at all. Alcohol tolerance, cold tolerance and nitrogen demand are the properties worth comparing.
- What is brettanomyces — *Brettanomyces*, correctly *Dekkera* in its spore-forming form, is a slow yeast that ferments sugars other strains leave behind and produces volatile phenols smelling of farmyard, leather or sticking plaster. In cider it is common and not always unwanted.
- Can you make cider from shop bought apple juice — Yes, provided the juice contains no preservative — check for potassium sorbate or benzoate on the label. Pasteurised juice ferments perfectly well once yeast is added, because pasteurisation removes the organisms but not the sugar.
Where to go next
- All compounds — Grouped by what the fruit brings and what the ferment makes of it.
- Sensory — Every descriptor, with the compound or process that causes it.
- Microbiology — The organisms whose metabolism most of this chemistry belongs to.
Sources
What this page rests on. Where a source is marked as registered rather than read, CiderHQ is recording that the body is authoritative on the subject without claiming to have worked through the document itself. See our evidence policy for what each state means.
Peer-reviewed literature on cider fermentation microbiology
Various journals · peer-reviewed literature · registered as competent for this subject
Covers the microbial succession of spontaneous cider fermentation, the role of non-Saccharomyces yeasts in the early stages, malolactic conversion by Oenococcus and Lactobacillus species, and the organisms behind the principal spoilage faults.
The Science of Cidermaking and associated technical writing
Andrew Lea · reference work · passage verified 2026-08-24
Written by a food chemist who worked at Long Ashton on apple phenolics. Unusual among specialist cider writing in that it is primary-research-adjacent: the author is describing work he did, and cites the literature. This is why it is registered at tier 1 for chemistry while a general cider book is not.
Hochschule Geisenheim University — beverage technology
Hochschule Geisenheim · university · retrieved 2026-08-24
German beverage-technology research covering apple wine and fruit juice processing, including the enzymology of clarification.