Organism
Lactiplantibacillus plantarum
A versatile lactic acid bacterium, renamed out of Lactobacillus in 2020, capable of malolactic conversion and of a range of faults depending on conditions.
Also called Lactobacillus plantarum.
- Kind
- Bacteria
- Binomial
- Lactiplantibacillus plantarum
- Role
- Malolactic conversion, Spoilage
What it does
- Converts malic acid to lactic acid via the malolactic enzyme, like Oenococcus, and is used commercially as a malolactic starter where a rapid conversion at moderate pH is wanted.
- Ferments hexose sugars homofermentatively but can switch to heterofermentative metabolism on pentoses, so its by-product profile — and its contribution to volatile acidity — depends on what substrate it finds.
- Carries a broad enzymatic repertoire including glycosidases and esterases, which can alter a cider’s aroma beyond the acid conversion itself.
- Produces biogenic amines from amino acids in some populations, and can generate off-flavours where it grows in a cider that still contains sugar.
- Is one of the two lactic acid bacteria actually recovered from working Asturian cider cellars during industrial malolactic fermentation, alongside Oenococcus oeni and Lactobacillus brevis, rather than one predicted from the wine literature.
- Has been used deliberately to acidify apple mash before fermentation rather than to deacidify cider after it — producing around a gram of lactic acid per litre and lowering pH by three to four tenths — which is the opposite of the role it plays in malolactic conversion.
Conditions it works in
What the organism tolerates and what suppresses it. These are the levers a maker actually has: temperature, acidity, air, alcohol and sulphite.
| Condition | What is recorded |
|---|---|
| Temperature | Grows across roughly 15 °C to 35 °C, faster and more reliably warm than *Oenococcus*. |
| pH | Less acid-tolerant than *Oenococcus*: growth is unreliable below about pH 3.4 and comfortable above pH 3.5. |
| Oxygen | Facultatively anaerobic; grows with or without air. |
| Alcohol tolerance | Moderate, generally to around 10–12% ABV. |
| Sulphite tolerance | Sensitive; free sulphur dioxide inhibits it. |
What it produces
Compounds this organism makes. Which organism made a compound usually decides whether it reads as a feature or as a symptom.
Lactic acid
The softer acid that replaces malic when malolactic fermentation runs, halving the acid a cider carries and changing its texture as much as its sharpness.
Acetic acid
The vinegar acid, made by bacteria oxidising ethanol whenever air reaches a cider, and the one fault in cider that no later processing can undo.
Carbon dioxide
The other product of fermentation, which protects a cider from air while it is being made and, dissolved in the finished drink, changes both its texture and its perceived acidity.
Diacetyl
The butter compound, made mainly by lactic acid bacteria and perceptible at very low concentration, which is a defining part of some traditional ciders and an obvious fault in others.
Biogenic amines
Amines produced when bacteria decarboxylate amino acids, associated with long lees contact at high pH and low sulphite, and a reason bacterial activity is managed rather than simply tolerated.
Ethyl lactate
The slow-forming ester of lactic acid and ethanol, which accumulates after malolactic fermentation and contributes the soft, milky roundness of a long-matured traditional cider.
Faults it causes
Faults this organism is implicated in. Several are faults only against a particular expectation — the same activity is a signature elsewhere.
Lactic off-flavours
Sauerkraut, sour milk, silage or cheesy notes from lactic acid bacteria working on sugars and other substrates rather than on malic acid alone.
Low acidity
A cider without enough acid to give it definition, tasting soft, heavy and dull — and sitting at a pH that leaves it exposed to spoilage organisms.
Volatile acidity
The measurable fraction of acidity that can be steam-distilled off, dominated by acetic acid and read as vinegar sharpness in the nose and a hard, hot finish.
Mousiness
A retronasal taint of mouse cage, stale popcorn or crackers that appears only after swallowing — and that a substantial fraction of people cannot detect at all.
Microbial haze
Cloudiness caused by a growing population of spoilage organisms, and therefore a symptom of something worse rather than a clarity problem in itself.
Excess diacetyl
A butter, butterscotch or popcorn character from diacetyl, produced by lactic acid bacteria metabolising citric acid, and by yeast under stress.
Acrolein bitterness
An intense, lingering bitterness quite unlike tannin, produced when lactic acid bacteria convert glycerol to acrolein and the acrolein reacts with the cider’s phenolics.
Excessive acidity
Acidity high enough to dominate everything else, leaving a cider that is thin, hard and sour rather than fresh.
Geranium taint
A sharp, unmistakable crushed-geranium-leaf smell produced when lactic acid bacteria metabolise sorbic acid added as a preservative.
Where in the process it appears
Malolactic fermentation
A bacterial conversion of sharp malic acid into softer lactic acid, which lowers acidity, changes aroma, and in most traditional cider happens whether it was planned or not.
Tank maturation
Resting cider in stainless steel or a lined vessel, where the point of the container is that it contributes nothing and admits almost no oxygen.
Sulphiting
Adding sulphur dioxide to juice to suppress spoilage organisms and oxidative browning, at a level that only means anything once the juice pH is known.
Fermentation monitoring
Watching a running ferment through gravity, temperature, smell and surface behaviour, and reading the rate of change rather than any single figure.
Sanitation
The cleaning and sanitising discipline that underlies every other process, and why removing soil must come before any attempt to kill organisms.
Microbial succession
The ordered handover of a spontaneous ferment from apiculate yeasts to *Saccharomyces* to lactic acid bacteria, and the spoilage organisms waiting at the end of it.
Acid balancing
Bringing a cider to the sharpness it needs, which requires separating perceived sharpness from titratable acidity from pH — three related things that do not move together.
Secondary fermentation
Any fermentative event that follows the primary ferment — residual sugar refermenting, a deliberate second alcoholic fermentation, or the malolactic conversion of the maturation phase.
Sorbate stabilisation
Adding potassium sorbate to prevent yeast from restarting a fermentation in the package — an inhibitor rather than a killer, and one that must never be used without sulphite.
Described in full
- The reaction
- Malic acid, which carries two acid groups, is decarboxylated to lactic acid, which carries one, releasing carbon dioxide. Nothing is fermented in the ordinary sense: no sugar is consumed and no alcohol is made.
- What performs it
- Lactic acid bacteria, chiefly Oenococcus oeni and Lactiplantibacillus plantarum. They arrive on the fruit and in the vessel, and in traditional cidermaking they are rarely inoculated.
- Acidity falls
- Losing one of two acid groups roughly halves the acid contribution of every malic molecule converted. Titratable acidity drops and the cider tastes rounder.
- pH rises
- The same change raises pH, which matters because a higher pH is a less protected cider. Malolactic makes a drink softer and simultaneously more vulnerable to spoilage.
- A buttery note may appear
- Diacetyl is a by-product. In small amounts it reads as butter or butterscotch, which is traditional in some styles and a fault in a fresh, fruit-driven one.
- Carbon dioxide is released
- A slow bead in a maturing vessel is often malolactic rather than residual fermentation. In a sealed bottle, an unfinished malolactic is a source of unplanned pressure.
- Not always wanted
- A cider made for freshness is usually kept below the pH and temperature where the bacteria establish, or filtered and sulphited to prevent it. The same conversion is a goal in one cellar and a fault in another.
About Lactiplantibacillus plantarum
The name change is recent and worth stating carefully. In 2020 a large taxonomic revision split the genus Lactobacillus, which had become unmanageably broad, into twenty-five genera. Lactobacillus plantarum became Lactiplantibacillus plantarum. The organism did not change; almost all the literature predating the revision uses the old name; and both names will appear in laboratory reports and technical writing for years. CiderHQ uses the current binomial and records the former one as an alias rather than pretending the change never happened or that it is settled in everyday usage.
Its position in cider is between a tool and a hazard. Where a juice sits at moderate pH and a maker wants malolactic conversion completed quickly and warm, L. plantarum is a legitimate choice and is sold for the purpose; its homofermentative metabolism on hexoses means it adds less acetic acid than a heterofermentative organism would, provided the sugar is gone. Where a cider is still sweet, the same metabolism becomes a problem, because the organism will not confine itself to malic acid.
The pH threshold is the practical dividing line between this species and Oenococcus oeni. Below roughly pH 3.4 Oenococcus has the advantage and L. plantarum struggles; above pH 3.5 the reverse increasingly applies. Cider frequently sits above that line where wine does not, which is one reason cider malolactic populations are more diverse than wine ones and less predictable in what they produce.
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.
- How long does cider take to ferment — A warm ferment with cultured yeast can finish in one to two weeks; a cool wild ferment in a cellar may take three months or more. Slow is not the same as stuck — the test is whether gravity is still falling.
- Can you fix a cider that has gone vinegary — Not really. Volatile acidity cannot be removed at small scale, and blending it away only dilutes it. The realistic options are to accept it, to blend a lightly affected batch into a much larger sound one, or to let it finish becoming vinegar.
- How do i sterilise cider bottles — Wash them clean first, then sanitise with a no-rinse sanitiser or a sulphite solution, and fill while still wet with it. Bottles that look clean but have dried deposits inside are the usual source of bottle spoilage.
- What is malolactic fermentation — Malolactic fermentation is a bacterial conversion of sharp malic acid into softer lactic acid, releasing carbon dioxide. It lowers total acidity and raises pH, and in cider it is often the source of a farmyard or buttery note as well.
- What is mousiness in cider — Mousiness is a fault caused by tetrahydropyridines produced by *Brettanomyces* and some lactic acid bacteria. It tastes of stale grain or a mouse cage and appears in the aftertaste rather than in the aroma.
- Why is sulphite added to cider — Sulphur dioxide suppresses spoilage bacteria and wild yeast before fermentation and protects the finished cider from oxidation. How much of it is active depends strongly on pH, which is why low-acid juice is harder to protect.
Where to go next
- All organisms — Grouped by what each does in the ferment, and by what kind of organism it is.
- Compounds — The chemistry this microbiology produces.
- Troubleshooting — Work from the symptom in the glass back to the organism.
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.
Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA)
Principado de Asturias · research institute · retrieved 2026-08-24
The Asturian regional agri-food research service, and the technical authority behind the Asturian cultivar classification and the analysis of sidra natural. SERIDA’s own site has not been opened; what CiderHQ has read is SERIDA’s varietal characterisation as republished by the Consejo Regulador of DOP Sidra de Asturias, which credits it explicitly. The Asturian measurements therefore cite the Consejo rather than SERIDA — citing the body that did the work, at a document CiderHQ has not seen, would be exactly the kind of borrowed authority this register exists to prevent.
Prevalent lactic acid bacteria in cider cellars and efficiency of Oenococcus oeni strains
Sánchez, Coton, Coton, Herrero, García and Díaz, Food Microbiology 32(1):32–37 · peer-reviewed literature · retrieved 2026-08-24
Which lactic acid bacteria are actually in working Asturian cider cellars, rather than which ones the wine literature would predict. Bibliographic record verified through Crossref on 2026-08-24 and the abstract read; the full text is paywalled on ScienceDirect. Cited for the identification of the prevalent species and for the finding that strains sort by producing area, not for any figure.
Enhancing fruit spirit quality: Novel approaches to mash acidification techniques
Fejzullahu, Kun-Farkas and Kun, Acta Alimentaria 53(3):360–372 · peer-reviewed literature · retrieved 2026-08-24
Registered because it is the one study CiderHQ found that tests biological acidification on apple mash rather than on grape must. That distinction matters: the extensive Lachancea thermotolerans literature is a wine literature, and a result obtained in grape juice at pH 3.5 with 220 g/L of sugar does not transfer to apple juice at pH 3.9 with 110. Bibliographic record verified through Crossref and the abstract read on 2026-08-24; the full text is behind the publisher’s wall.