Equilibrium cure and equilibrium brine

Salt percentage

How much salt to weigh out for a target percentage, dry or in a brine, and what strength that brine starts at.

An equilibrium cure doses the salt against the meat and lets the whole of it go in. An equilibrium brine doses it against meat and water together, so that when the two have equalised the meat sits at the target.

The distinction that catches people is between salt percentage and brine concentration. They are different denominators and they give different numbers for the same product.

Calculate

Meat (g)

Water added (g)

Zero for a dry equilibrium cure. Any figure above zero makes it an equilibrium brine.

Target salt (% of meat)

Salt to weigh out

50.0 g

Working

A dry equilibrium cure doses the salt against the meat alone.

salt = meat x target / 100
     = 2,000.0 x 2.50 / 100
     = 50.00 g

Everything weighed out goes on the meat and stays there, so
the finished salt percentage is the target, whatever happens
to the timing.

Salt percentage is not brine concentration. FSIS defines brine concentration as 100 x salt / (salt + water), so it is measured against the water in the product rather than against the whole product. A 2.5 percent salt cure on a lean muscle reaches a much higher brine concentration than the same cure on a fatty one.

Worked example

A dry equilibrium cure at 2.5 percent on 2,000 g of meat.

salt = 2,000 x 2.5 / 100 = 50.0 g

If that meat is 70 percent water, the brine concentration it
reaches once equalised is:
  100 x 2.5 / (2.5 + 70) = 3.45 percent

The same cure on a belly at 45 percent water reaches:
  100 x 2.5 / (2.5 + 45) = 5.26 percent

Two pieces at the same salt percentage, at different brine concentrations, because they hold different amounts of water. This is why the published thresholds are stated against brine concentration and not against salt percentage.

What this does not tell you

Equilibrium is a destination, not a schedule. Reaching it takes time that depends on the thickness of the piece.