Comparison
Malolactic vs no malolactic
What does malolactic fermentation do to cider?
In short
Lactic acid bacteria, chiefly Oenococcus oeni and Lactobacillus species, decarboxylate malic acid to lactic acid. Since malic is a dicarboxylic acid and lactic is monocarboxylic, the perceived acidity falls substantially, and the texture softens.
It is not only a change in acid. The conversion can bring diacetyl, and in cider it is associated with phenolic and spicy notes that many traditional English and French ciders carry as part of their character. It also consumes a substrate that would otherwise be available to spoilage organisms later.
Preventing it — by sulphiting, cold storage, filtration or early bottling — keeps a cider brighter and sharper. Whether that is wanted depends on the acid the cider started with and on the style. In perry it is a more delicate question, because pear juice also carries citric acid, which some lactic bacteria convert to acetic acid and diacetyl.
The two things being compared
Each side described in its own terms first, so the table below has something to hang on.
Malolactic conversion
Bacterial conversion of malic acid to lactic acid, lowering total acidity, softening texture and adding lactic and phenolic character.
No malolactic conversion
Malic acid retained. The cider stays sharper and fresher, and the aromatic contribution of the bacteria is absent.
Where they differ
Dimension by dimension. Where a row needs a qualification, it carries one rather than being simplified until it fits.
| Dimension | Malolactic conversion | No malolactic conversion |
|---|---|---|
| Acid | Total acidity falls markedly as malic becomes lactic. | Malic acid intact. |
| Texture | Softer and rounder. | Sharper and more angular. |
| Aroma | Lactic, buttery or spicy notes; diacetyl at higher levels. | Fruit and fermentation esters, undisturbed. |
| Microbial stability afterwards | Improved, because malic acid is no longer available as a substrate. | Malic acid remains, so an unwanted conversion is still possible in the package. |
| Control | Encouraged by warmth, low sulphite and lees contact; can be inoculated. | Prevented by sulphiting, cold, filtration or early bottling. |
| Risk in perryThe calculation is genuinely different in perry, which is why perry makers are more likely to suppress it. | Citric acid in pear juice can be converted to acetic acid and diacetyl by some strains. | Avoids that route entirely. |
| Where it is normal | Traditional English, Norman and Breton cider, often occurring spontaneously over winter. | Modern clean-fermented ciders and most commercial production. |
Notes under a dimension name qualify the whole row, not one column.
When Malolactic conversion is the relevant one
The circumstances in which this is the thing being described, rather than a reason to prefer it.
- The cider is high in acid and softening is wanted.
- You are explaining spicy or buttery notes in a traditionally made cider.
- Stability against later bacterial activity matters more than freshness.
When No malolactic conversion is the relevant one
The circumstances in which this is the thing being described, rather than a reason to prefer it.
- The cider is already low in acid and cannot spare any.
- The style depends on fresh fruit character.
- The drink is a perry, where the citric acid route carries a real risk.
A misconception worth clearing up
This comparison exists partly because of the claim below, which is repeated often enough that most readers arrive holding it.
Malolactic fermentation is a fault, because it involves bacteria.
What is actually the case: It is a normal and often intentional part of traditional cider-making, and the same organisms are used deliberately in winemaking. It becomes a problem when it happens in the bottle rather than in the vessel, or when the strains involved also attack citric acid, glycerol or residual sugar.
Related comparisons
Distinctions that turn on the same thing, or that this one is routinely confused with.
Wild vs cultured fermentation
A wild ferment runs on the yeasts already present on the fruit and in the building; a cultured one is started with a selected strain in sufficient quantity to dominate from the beginning.
Cider vs perry
Cider is fermented from apples and perry from pears — but the pear brings sorbitol, citric acid and stone cells, which change how the drink ferments, how sweet it finishes and how it must be handled.
Sulphited vs unsulphited
Sulphur dioxide suppresses spoilage organisms and binds oxidation intermediates; working without it means relying on hygiene, low pH, temperature and vessel management instead.
Fault vs style feature
Many of the compounds recorded as faults are present in well-regarded traditional ciders. What separates a fault from a feature is concentration, integration and whether the producer intended and controlled it.
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.
- What is the difference between cider and perry — Cider is fermented apple juice and perry is fermented pear juice. Perry is lower in tannin, higher in unfermentable sorbitol so it tastes faintly sweet even when dry, and considerably harder to make.
- What is the difference between wild and cultured fermentation in cider — A wild fermentation is carried by the yeasts already on the fruit and in the press house, in a succession of species; a cultured one is started by pitching a single chosen strain. Wild ferments are slower, more variable and can carry aromas a single strain does not make.
- When is a cider faulty and when is it just traditional — The same compound can be either, and the deciding factor is the tradition the cider belongs to and the concentration. Volatile acidity that would condemn a modern fresh-fruit cider is expected in a traditional Asturian one, and neither judgement is wrong.
- Why is sulphite added to cider, and what happens if it is not — Sulphite suppresses spoilage organisms and binds oxidation products, and its effectiveness depends sharply on pH — at pH 3.8 it is a fraction as potent as at pH 3.2. Unsulphited cider is entirely possible and is the tradition in several regions, but it carries more risk and less shelf life.
Where to go next
- All comparisons — The rest of the pairs, grouped by what kind of difference is at stake.
- Glossary — Either term on its own, defined without a second thing to hold it against.
- Learn about cider — The background these pages assume, written from the beginning.
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.
Research on pear juice composition and sorbitol in perry
Various journals and institute reports · peer-reviewed literature · registered as competent for this subject
The evidence base for the single most important chemical difference between cider and perry: pears carry substantial sorbitol, which yeast does not ferment, so a fully fermented perry retains sweetness a fully fermented cider cannot.