Fermentation planner
Batch size in. Culture, dextrose, fermentation conditions and a hard time limit out — then a pH gate you must pass before the salami goes to dry.
This is a calculator, not a tested recipe. It plans the numbers; it can't see your culture, chamber or meter. When in doubt, follow an established recipe from a trusted source.
Salt and cure for the batch come from the dry cure calculator (choose "Ground").
pH gate — before it goes to dry
Why this matters
A fresh salami sits warm and wet for a day or two — ideal for the lactic bacteria you added, and for Staphylococcus aureus, whose toxin cooking won't destroy. The race is won when acid drops the pH to 5.3 or below. USDA-referenced industry guidance sets a hard ceiling on how long that race may take, counted in degree-hours: warmer is faster for both sides, so the time allowed shrinks as the temperature rises. Miss the window and the batch is out. Pass it, and drying can begin.
Notes
- Degree-hours: American Meat Institute Foundation, Good Manufacturing Practices for Fermented Dry & Semi-Dry Sausage Products (1997), referenced by USDA FSIS for S. aureus control. Degree-hours = hours × (°F − 60), summed over each temperature stage. The product must reach pH 5.3 within 1,200 degree-hours if the highest fermentation temperature is below 90 °F (32.2 °C), 1,000 between 90 and 100 °F, and 900 above 100 °F.
- Culture dose: most freeze-dried meat cultures sold to home producers are dosed at 25 g per 100 kg of meat (0.25 g/kg), but not all — use the number on your packet. Rehydrate in a little chlorine-free water as the packet directs. Fast cultures (for example Bactoferm F-RM-52) are built for 22–26 °C; traditional cultures (for example T-SPX) for about 18–24 °C. Check your culture's data sheet.
- Contested: how much dextrose. More sugar lets the culture make more acid and drives the pH lower and the flavor tangier. Common home ranges are 0.3–1% of batch weight; fast cultures usually take the higher end. No reliable formula maps a dextrose % to a final pH — it depends on the culture, the meat and the temperature. Measure the pH.
- Contested: drying schedule. The table is the pattern most published guidance follows — start humid and step down — not a USDA requirement. Diameter, casing and airflow change it. Too dry too early seals the surface (case hardening); too humid for too long invites unwanted mold and slime.
- What this doesn't cover: commercial fermented sausages must show a 5-log reduction of E. coli O157:H7, which fermentation and drying alone may not deliver; pork in uncooked products also carries a Trichinella consideration (source your pork carefully or follow a trusted freezing protocol). Use a calibrated pH meter (calibrate at 4.0 and 7.0); pH strips are not precise enough for a 5.3 gate.