Where every figure comes from

The maximums Brinescale uses

The words, and the arithmetic

The chart of curing agents in 9 CFR 424.21(c) allows sodium or potassium nitrite "to fix color" in "cured meat and poultry products" at "2 lb to 100 gal pickle at 10 percent pump level; 1 oz to 100 lb meat or poultry product (dry cure); 1/4 oz to 100 lb chopped meat", and adds that nitrite and nitrate "shall not result in more than 200 ppm of nitrite, calculated as sodium nitrite in finished product, except that nitrites may be used in bacon only in accordance with paragraph (b)".

Sodium or potassium nitrate is listed for these products: "Cured meat products other than bacon. Nitrates may not be used in baby, junior, and toddler foods. Cured, comminuted poultry or poultry products", at "7 lb to 100 gal pickle; 3 1/2 oz to 100 lb meat or poultry product (dry cure); 2 3/4 oz to 100 lb chopped meat or poultry". For poultry, then, the nitrate line names only comminuted (ground) products, so for a whole turkey breast or chicken Brinescale tells you to use Cure #1. Neither nitrite nor nitrate may be used in baby, junior or toddler foods.

A pound is 16 ounces, so 100 pounds is 1,600 ounces. Parts per million follow directly:

1 oz per 100 lb = 1 ÷ 1,600 = 625 ppm (dry cure, nitrite) 1/4 oz per 100 lb = 0.25 ÷ 1,600 = 156.25 ppm (chopped meat, nitrite) 3 1/2 oz per 100 lb = 3.5 ÷ 1,600 = 2,187.5 ppm (dry cure, nitrate) 2 3/4 oz per 100 lb = 2.75 ÷ 1,600 = 1,718.75 ppm (chopped meat, nitrate)

For brines and injected meat, Brinescale holds the recipe to that 200 ppm figure, counted on what goes in (ingoing).

Bacon has its own paragraph, 9 CFR 424.22(b). Injected and massaged bacon uses "120 parts per million (ppm) ingoing" sodium nitrite with "550 ppm of sodium ascorbate or sodium erythorbate"; the same paragraph also allows "100 ppm ingoing" with that 550 ppm of ascorbate, or "a predetermined level between 40 and 80 ppm" only with added sugar and a lactic-acid starter culture. Immersion-cured bacon "shall not exceed 120 ppm ingoing"; dry-cured bacon "shall not exceed 200 ppm ingoing ... based on the actual or estimated skin-free green weight of the bacon belly". Brinescale treats 120 ppm as the top for injected bacon. Nitrate is not allowed in bacon, so the calculator refuses Cure #2 for it.

The 120 ppm floor for refrigerated cured products

The regulations set maximums. FSIS, the agency that inspects meat plants, also has a floor, written in its Processing Inspectors' Calculations Handbook (FSIS Directive 7620.3):

"As a matter of policy, the Agency requires a minimum of 120 ppm of ingoing nitrite in all cured "Keep Refrigerated" products, unless the establishment can demonstrate that safety is assured by some other preservation process, such as thermal processing, pH or moisture control."

The same handbook says there is no regulatory minimum for cured products made shelf-stable by full cooking, pH or moisture control. Brinescale still prints a recipe below 120 ppm, but marks it, so that a low figure is a choice and not a slip.

FSIS Directive 7620.3, Processing Inspectors' Calculations Handbook (revised 1995), chapter 3. Read 2026-10-18 from the Internet Archive copy of FSIS's PDF (captured 2005-08-26).

Cold while it cures

Curing happens in the refrigerator. USDA's Food Safety and Inspection Service says refrigerators "should be set to maintain a temperature of 40 °F or below" (4 °C). Brinescale's result card says so for every dry rub, brine and injection. A dried or fermented product spends part of its time warmer than that by design: that is a process to learn from a tested recipe and your county Extension office, not from a calculator.

USDA FSIS, Refrigeration and Food Safety, read 2026-10-18 from the Internet Archive copy captured 2026-01-03.

What Brinescale divides by

• Dry rub: the meat's green weight (raw, before curing). All of the rub stays on the meat.
• Equilibrium brine: the meat plus the water. Salt and sugar are not added to that total, which makes the ppm read a little high: the safe side for a maximum.
• Injected brine: the meat's green weight. The nitrite in the injected brine is the brine's nitrite share times the pump percentage. If more brine goes in than planned, the ppm goes up in step; the result shows by how much.
• Sausage: the meat block (meat and fat), the way the rule is written ("per 100 lb chopped meat"). Water or ice added to the mix is not counted.

Curing salts differ a great deal. The calculator starts at 6.25 % sodium nitrite, the figure printed on many US Cure #1 packets, but some curing salts carry far less, so it always uses the percentage you type from your own label. If the label also lists sodium or potassium nitrate, it is a Cure #2 type: choose Cure #2 and type both figures, so the nitrate is counted and kept out of bacon and brines. Brinescale has no default for the nitrate, counts the rest of the packet as salt, and prints the curing salt rounded down to the last digit shown.

When to ask someone

• Selling, giving away or serving cured meat to the public: that is a regulated food business. Ask your state's meat inspection program or USDA's Food Safety and Inspection Service before you start.
• Your first dried, fermented or uncooked cured product (salami, coppa, country ham): ask your county Extension office, which has food-safety specialists for home food preservation. Weight loss alone does not show that a product is done or safe.
• You are not sure what your curing salt contains: stop and find the label or the maker's sheet. Do not guess the percentage.
• Curing salt is not table salt. Keep it labelled, away from the salt shaker and out of children's reach. If someone swallows curing salt, call Poison Control at 1-800-222-1222 (US).

Brinescale is a calculator. It is not a food-safety plan, it gives no medical, nutrition or health advice, and a recipe inside the limits is not a promise that the food is safe: that also depends on handling, temperature, time and drying. Brinescale is not affiliated with or endorsed by the USDA.