Culture & Starter Reference

A ferment is only as predictable as the microbes driving it. This page collects the working parameters for the cultures and starters used across the site: the temperature band each one prefers, the finished pH you are steering toward, and the typical time to get there. Use it to pick a culture, set up the environment, and know when to stop watching the thermometer and start tasting.

For the decision of whether to inoculate at all versus letting the wild population take over, see method-wild-vs-starter.

Cultures and starters

Culture	Temp band	Target pH	Typical days	What it does	Notes
Wild lacto (vegetable)	18–22 °C / 64–72 °F	3.4	7–28	Lactic-acid fermentation from microbes already on the vegetable	No inoculant needed; salt + anaerobic conditions select for Lactobacillus. Cooler = slower, cleaner.
Whey (strained from live yogurt)	18–22 °C / 64–72 °F	3.6	5–14	Lactic backslop; seeds the brine with active lacto bacteria	Speeds the start by 1–3 days; use 1–2 Tbsp fresh whey per quart. Not a salt substitute — keep salt in band.
SCOBY (kombucha)	21–27 °C / 70–81 °F	3.0	7–21	Acetic + lactic acids and a yeast/bacteria mat over sweet tea	Needs a starter liquid of mature, acidic kombucha (~10% by volume) to drop pH fast and out-compete mold.
Mother of vinegar (Acetobacter)	21–29 °C / 70–84 °F	3.0	14–60+	Oxidizes ethanol to acetic acid (aerobic)	Needs oxygen, not anaerobic. Cover with cloth, not a lid. Works on already-fermented alcohol.
Koji (Aspergillus oryzae)	27–32 °C / 81–90 °F	n/a	1.5–2 (~36–48 h)	Mold that saturates grain/legume with amylase + protease enzymes	A mold culture, not an acidifier — pH is not the endpoint. Drives miso, amazake, shoyu. High humidity, frequent temperature checks.

Note

Temperature is the single biggest lever on speed. Within a culture’s band, the warm end can roughly halve the time of the cool end — and push flavor toward sharper, less complex. The cool end is slower but generally cleaner and more nuanced. Pick the band, then pick your end of it for the result you want.

Reading the table

• Wild lacto is the default for cabbage, cucumbers, kimchi, hot sauce, and most vegetable ferments. Salt percentage and an anaerobic (submerged) environment do the selecting; you are not adding bugs, just favoring the right ones.
• Whey is a backslop shortcut: a spoonful of live-culture whey seeds the brine and shortens the lag phase. It does not replace salt — keep salt in the product band so the early, unselected window stays safe.
• SCOBY and mother of vinegar both make acid but in different ways: the SCOBY ferment is largely anaerobic-tolerant under its pellicle, while Acetobacter is strictly aerobic and must breathe. Don’t seal a vinegar.
• Koji is the outlier — it is a cultivated mold grown for its enzymes, and pH is not how you judge it. You judge koji by aroma (sweet, chestnut-like), white-to-pale-yellow color, and full mycelium coverage of the substrate.

Caution

For acid-producing ferments (lacto, kombucha, vinegar), the target pH is the safety gate, not the flavor preference. A wild lacto ferment that has not reached pH 4.6 has not crossed the botulism line and is not shelf-stable. Verify with a calibrated meter, not taste — taste is never a safety test. See safety-and-botulism and acidity-and-ph.

Tip

Starter liquid is the cheapest insurance you can buy. A splash of finished, acidic brine from a previous batch (or mature kombucha for tea) drops the starting pH and gives the culture you want a head start over molds and unwanted yeasts that thrive in the neutral early window.

See also

• method-wild-vs-starter — choosing between a wild ferment and an inoculated one
• lactic-fermentation — how the wild lacto sequence actually works
• time-and-temperature — the temperature/time trade-off in detail
• calc-ferment-predictor — estimate ready windows from your salt % and temperature
• ref-temperature-bands — the master temperature × product × time table
• ref-ph-targets — finished pH / TA targets per product