In an equilibrium cure you weigh the salt so that, once it has spread evenly through the meat and any water, the final salt level is the one you chose in advance, so the meat cannot become saltier than planned however long it waits. In an excess cure you surround the meat with more salt than it can absorb, and the salt level in the meat depends on how long it stays and how thick it is, which is why the parent article ends its dry cure with a soak.
Part of Large-Scale Smoking & Curing
Equilibrium and excess curing are two ways of controlling salt in cured meat: fixing the amount of salt added relative to the weight of meat and water, or supplying salt in surplus and stopping the cure by time.
Two Ways To Get Salt Into Meat
Excess salt is the traditional method. The meat is rubbed, packed or immersed with more salt than it will take up. Salt moves in, driven by the difference between the salty surroundings and the unsalted meat, until the cure is stopped by removing the meat. The result depends on time, thickness and temperature, and the meat will keep taking up salt as long as it is in contact. The parent’s dry cure is of this kind: it adds 8 lbs of salt per 100 lbs of meat, yet then tells you to rinse and soak the meat to reduce saltiness, which only makes sense if the cure leaves the meat saltier than you want (Dry cure ratios and rub formulas).
Equilibrium curing turns the calculation around. Decide the final salt fraction you want in the finished meat, weigh the salt to give exactly that, and wait until it has spread evenly. The end point is set by the arithmetic, not by the clock; waiting longer cannot over-salt the meat. The clock only decides when the centre has caught up (Curing times by thickness).
Worked Example: A Wet Equilibrium Cure
In an idealised case, salt ends up spread through all the meat and brine water together. The salt needed is then
salt = target fraction × (weight of meat + weight of water).
Take 10 lbs of meat in 1 gallon (8.34 lbs) of water, and choose a target of 2.5% of the total weight, as a purely illustrative number and not a recommended or safe target (a safe target for a given product comes from a tested source):
- Total weight: 10 + 8.34 = 18.34 lbs
- Salt: 0.025 × 18.34 = 0.46 lbs, about 7.3 oz
- Check: in the water phase, with about 7 lbs of the meat’s weight as water (a 70% assumption), salt ÷ water = 0.46 ÷ (8.34 + 7) = about 3.0%
If the cure then goes on longer than needed, nothing changes. Compare this with the parent’s 1 lb of salt per gallon, which in the same case ends near 6.5% in the water phase and 1 lb of salt in the system (Wet brine concentrations): the equilibrium cure is a calculated amount, and the excess one is a rule of thumb.
Why The Distinction Matters For Safety
Salt is not the only thing in a cure that must be dosed. If a nitrite product is used, the amount that gets into the meat is set by the amount added relative to the meat’s weight. In an equilibrium cure you can control that. In an excess cure the surroundings carry far more cure than the meat takes up, and the dose that reaches the meat depends on time and thickness, which you cannot easily measure. For that reason do not use an excess method with a nitrite product, and where nitrite is used at all, use a weighed, equilibrium approach from a tested source.
The cost of equilibrium curing is that it needs a scale, a calculation and a wait; the cost of excess curing is a saltier or less predictable product, an extra soak, and a lot more salt used. Where salt is the scarce resource (Salt Production & Sourcing), equilibrium curing also stretches the supply.
What You Need
- A scale, and a note of the weight of every piece
- A calculation of the salt per batch written down before mixing
- A vessel and cold space as for any cure
Method: Choose The Method
Step 1: For small cuts, fish and poultry in a brine, use the equilibrium calculation with a target from a tested source.
Step 2: For large dry-cured cuts, follow the parent’s ratio and time, treating it as an excess method that needs a soak.
Step 3: Never combine methods in a batch. Record the method on the batch label.
Common Mistakes
- Calculating from the meat’s weight alone, forgetting the weight of the brine water.
- Treating the target as a safe level without a source that says it is.
- Using an excess method with a nitrite premix.
Safety
The dose of any curing poison is set by the arithmetic
Sodium nitrite and saltpetre are acutely toxic in small amounts, and the safety of a cure that uses them lies entirely in the weighing. This article gives no quantity because none can be sourced here. Never “add a bit more” to a cure, never keep curing premix next to table salt, and never use it by volume. See Cold-smoked sausages and bacon for the full hazard.
What’s Next
- Learn next: Curing times by thickness — why the time to the centre is controlled by thickness
- Combine with: Hot Smoking — the cooked alternative when a cure cannot be verified