Checking Saltpetre Use

[Liz]

Hello, I'm new here and new to meat curing, although I've been making fresh sausages for a while. I just want to check that I've understood the bits and pieces I've dredged up on using nitrates/nitrites: sticking mainly to saltpetre for now, because that's what I've bought.

I'd appreciate it if one of those with knowledge in this area could quickly check that I haven't wildly misunderstood, and won't poison my friends and family!

Nitrates and/or nitrites are added to cured meat:

1. to prevent botulism
2. to achieve a safe cure without using excessive (unpalatable) levels of salt
3. to assist in developping a particular flavour
4. to keep the meat pink rather than grey

Potassium or sodium nitrate and potassium or sodium nitrite are the salts used. The nitrites are what prevents botulism and keeps the meat pink. Nitrates are converted to nitrites in the meat during the curing process. Saltpetre is potassium nitrate (KNO3, E252).

For a dry cure, modern recommendations are 0.5g or saltpetre per Kg of meat (500 ppm) and around 3% salt (30g per Kg of meat).

For a wet cure it's more complicated, but the meat will absorb approximately 10% of its weight in brine, so that quantity of the brine should contain the amounts calculated for the dry cure. ie 1 Kg of meat will absorb 100g (approx 100 ml) so if you're using 1 L it would need to have 10 times the amount of salt and saltpetre that you'd use to dry cure the same piece of meat: it would need 5g of saltpetre and 300g salt.

My first project is to make a spiced beef recipe from Eliza Acton (1845). For 20 lb beef, she gives 7 oz sugar, 8 oz salt, 3/4 oz saltpetre - as well as various spices.

Salt: 0.5/20 = 0.025 = 2.5% So it's probably close enough to stick with her quantity.

Saltpetre: 0.75/(20*16) * 1,000,000 = 6250 which is a lot bigger than 500
20 lb/2.2 = 9.1 Kg
500 ppm or 0.5 g/Kg gives: 9.1*0.5 = 4.5g

My meat (brisket) weighs 2Kg (4.4 lb), so I'll use 3 oz salt and 1g saltpetre.

A final question (this one about taste, not safety) - the sugar scales down to about 2.5 oz for my piece of meat. Does that sound reasonable, or is it likely to be too sweet for modern tastes?

Sorry to go on so long, but I get the impression this is not something I want to get wrong.

[Oddley]

Hi Liz welcome to the forum
Where did you learn all this? It took me months to learn this subject. I think you have right all the reasons for using Nitrates / Nitrites.

For a wet cure it's more complicated, but the meat will absorb approximately 10% of its weight in brine, so that

quantity of the brine should contain the amounts calculated for the dry cure. ie 1 Kg of meat will absorb 100g (approx 100 ml) so if

you're using 1 L it would need to have 10 times the amount of salt and saltpetre that you'd use to dry cure the same piece of meat:

it would need 5g of saltpetre and 300g salt.

With Brine / Pickle cures it can be complicated. You are right that meat will absorb 8 - 10% of it's own weight. I don't think it's just a case of saying 10 times more you must take into account the weight of the brine with all the water soluble components of it. I hope the following formula explains this.

The other ingredient weights include sugar, salt etc. IN GRAMS
Weight of water (per gal) @ 60 degrees F
1 Gallon (US) = 8.337 045 264 109 35 lbs
1 Gallon (UK) = 10.022 266 313 9 lbs

My first project is to make a spiced beef recipe from Eliza Acton (1845). For 20 lb beef, she gives 7 oz sugar, 8 oz

salt, 3/4 oz saltpetre - as well as various spices.

Salt: 0.5/20 = 0.025 = 2.5% So it's probably close enough to stick with her quantity.

Saltpetre: 0.75/(20*16) * 1,000,000 = 6250 which is a lot bigger than 500
20 lb/2.2 = 9.1 Kg
500 ppm or 0.5 g/Kg gives: 9.1*0.5 = 4.5g

My meat (brisket) weighs 2Kg (4.4 lb), so I'll use 3 oz salt and 1g saltpetre.

Liz when calculating this stuff I would suggest you convert all the weights to grams and then calculate. Other wise it is pretty confusing. The underlined calculation is not correct. I like to be pretty accurate so don't use estimate amounts much. From my research 500 ppm Saltpetre is right.

453.592gm * 20 lbs = 9071.84 gm
28.3495gm * .75 oz = 21.262125 gm

ppm = Grams Nitrate * 1,000,000 / Grams of Meat

ppm = 21.262125 * 1,000,000 / 9071.84 = 2343.75

.: ppm or mg/kg = 2343.75

The preceding calculation can be used to check your ingoing amounts of nitrate / nitrite for dry cures. I normally use 2% sugar so can't say if 2.5% would be too sweet. 2% salt is what I use.

For 2 kg meat 1 gm of salpetre seems fine.
For 2 kg meat 3 oz or 85 gm salt = 4.25% for 2% use 40 gm or 1.5 oz which will give you 2.13%.

Phew my brain hurts.

[Liz]

Thank you very much, Oddley. I put together the stuff above from what I picked up on this BB and some of the articles linked from it. It's the result of a couple of days of intermittent browsing - but that was only possible because of the work you and a couple of others had done in digging it all out from all over the place.

I'll think a bit harder if I want to put together a wet cure. The one I'm doing now is dry, so a lot simpler to calculate.

I've just started the cure - rubbing the sugar, spices and saltpetre mix into the meat. It has to sit for 3 days, then the salt is added, and rubbed in daily for 12 days. Given that a whole brisket is basically just longer than my small joint, not thicker, I assume I should stick to the original timings rather than scaling them down.

[Oddley]

Yes keep to the original timings, When I use Nitrate, I like to give it at least 14 days no matter how small the size meat. This gives time for the various chemical reactions to take place.

My congratulations on finding out so much is such a short time.