CureSafe

Equilibrium curing (often abbreviated as EQ curing) is the gold standard method for charcuterie artisans, dry-curing enthusiasts, and home butchers. Unlike traditional excess-salting methods or mystery brine recipes that rely on unpredictable saturation gradients, equilibrium curing uses exact percentage calculations relative to the combined weight of meat and liquid.

Why Precise Weight Measurement Matters

Sodium nitrite (NaNO₂) serves two fundamental functions in cured meats: it prevents spores of Clostridium botulinum from germinating into deadly botulinum toxin, and it reacts with myoglobin to produce the iconic cured pink color and savory charcuterie flavor profile. However, nitrite is toxic in high doses.

What the USDA Actually Limits

There is no single legal nitrite number. 9 CFR 424.21(c) caps ingoing sodium nitrite by product class, and it states the allowance as a weight per hundredweight rather than as a concentration: 1/4 oz to 100 lb chopped meat, 1 oz to 100 lb for a dry cure, 2 lb to 100 gal of pickle at a 10 percent pump. Reduced to parts per million those are 156 PPM for comminuted product, 200 PPM for immersion cured, 200 PPM for massaged or pumped, and 625 PPM for dry cured. Dry sausage is chopped meat, so salami and soppressata sit in the comminuted class at 156 PPM — not in the 625 PPM dry-cured class, whose entries are whole-muscle products such as country ham and prosciutto.

The same section separately caps residual nitrite in the finished product at 200 PPM calculated as sodium nitrite. That is a measurement taken after curing, on a different basis from the ingoing figure this calculator computes, and it is the source of the widespread belief that 200 PPM is a universal ceiling. It is not one: dry-cured product is allowed 625 PPM ingoing.

Bacon is not covered by 424.21(c) at all. That section excludes it and sends bacon to 9 CFR 424.22(b), which sets 120 PPM ingoing for pumped or massaged bacon, not to exceed 120 PPM for immersion-cured bacon, and not to exceed 200 PPM for dry cured — all measured on the actual or estimated skin-free green weight of the belly. Potassium nitrite equivalents are 148, 148 and 246 PPM. A wet-brined bacon at the 156 PPM figure people quote for sausage is 30 percent over its own federal ceiling.

One basis difference matters for brines. FSIS measures ingoing nitrite against the meat block, not the whole formulation; equilibrium curing measures it across meat plus brine, which is what this calculator does. On a 2,500 g belly in 2,000 g of water, a 156 PPM equilibrium target puts 11.23 g of cure #1 in the bag — 0.70 g of nitrite. That is 156 PPM of the 4,500 g batch and 281 PPM against the green weight FSIS would measure. The equilibrium figure is the useful one for a home curer, because the meat lands near the target instead of absorbing everything you add. It is not the number a federally inspected plant is held to.

The Core Equilibrium Mathematical Formulas

To calculate the exact mass of Prague Powder #1 required for any batch, CureSafe uses the mass fraction formula that follows from its 6.25% nitrite content. Prague Powder #2 carries the same 6.25% nitrite, so the dose is identical; only the salt back-off below differs.

Because Prague Powder #1 is 93.75% pure table salt by weight, failure to account for its salt content will over-salt your meat. CureSafe subtracts the sodium chloride already present in the curing powder, using each compound's own fraction: 0.9375 for Prague Powder #1 and 0.8975 for #2, whose remaining 4% is sodium nitrate rather than salt.

Equilibrium Wet Brine vs. Equilibrium Dry Cure

• Equilibrium Dry Cure: Salt, curing salt, and spices are rubbed directly onto the meat surface before vacuum sealing or zip-bagging. Total mass equals meat mass. Over-curing is impossible—once the meat absorbs all the salt, it reaches exact equilibrium.
• Equilibrium Wet Brine: Meat is submerged in a water solution. The salt and nitrites diffuse across both the water and meat until equal concentration is reached. Total mass equals Meat Weight + Water Weight.