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Experiment: Saltpeter vs. Nitrite For Curing Salami

Air dried salami is a treat that unfortunately is hardly ever made in Germany. Here Salami (just as the closely related Mettwurst) is usually smoked and only cured for a relatively short period. The classic salami country is Italy which is not very surprising since this method of sausage making was already practiced by the Romans. But also in France, Spain and other mediterranean countries this type of sausage is made.

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Salami is a raw meat sausage. To make the meat shelf stable it needs to be dried to an extent that no harmful bacteria can thrive. A fairly strong dose of salt helps this process. But until the water content of a sausage as fallen to a secure level it takes several weeks. To prevent bacteria from doing harm during this period the salt is enriched with nitrate or nitrite.

Nitrite has the property to kill off  many different bacteria includuing the dangerous clostridium botulinum whose metabolite botox causes the potentially lethal botulism. Unfortunately those bacteria feel particularly well in the conditions used for sausage curing: moisture and lack of oxygen inside the sausage.

Only in fairly recent times nitrite has been used for curing meat because it is hardly found in nature. The classic method of making salami uses nitrate from saltpeter (mainly potassium nitrate, KNO3). Nitrate has almost no antibacterial properties, though. Why sausage making works anyway could only be understood when the biochemical processes during curing could be researched better: bacteria present in the meat can convert nitrate to nitrite.

Unfortunately this conversion happens rather slowly, so saltpeter cured salami always needs to be aged and dried for several weeks. Nitrite cured sausage on the other hand can be consumed immediately, even if it is still moist inside.

Furthermore the nitrite also causes the reddening of the meat that happens when the sensitive myoglobin that gives raw meat its red colour is converted to a chemically more stable form, the nitrosomyoglobin, via intermediate steps.

Despite the obvious advantages of nitrite curing saltpeter still is used for traditionally made sausages, especially in France but also in Italy. In Germany the use of nitrite has almost completely taken over with a few exceptions like “Ahle Wurscht” from northern Hessen. Why ist saltpeter still used? I have found two main arguments for the use of saltpeter: a nicer colour and a better taste.

To find out if this really is true, I decided to make an experiment. I made two batches of simple salami after a French recipe for “saucisson pur porc”, using either nitrite or nitrate.

I cured the sausages in my cellar that currently provices good conditions with 11 to 12 degrees and 70% to 70% relative humidity.

Ingredients per kg:

  • 700 g lean pork (ham or shoulder)
  • 300 g raw pork fat
  • 5 cl red wine
  • 5 g sugar
  • 2 g black pepper
  • 0,5 g ascorbic acid
  • 0,5 g Bactoferment 61
  • Natural hog casings 36/38 mm

Half of the sausage meat was cured with 26 g German nitrite curing salt (0.5% nitrite content), the other half used 25.5 g table salt and 0.5 g potassium nitrate.

The addition of ascorbic acid (also known as Vitamin C) is no evil plot of the food industry as one might guess on first thought. It rather is helpful in converting excess nitrite to nitric oxide which then is dispersed in the air. This conversion also happens naturally but the process is much slower. So the ascorbic acid helps to reach keep the nitrite level as low as possible.

Bactoferment 61is a starter culture with bacteria for the conversion of nitrate into nitrite as described above. They are also naturally present in the meat but adding the starter culture helps to suppress the growth of harmful bacteria.

The sugar serves as food for the lactic bacteria that create a slightly acidic environment which is bacteriologically benefitial.

Peraration:

Meat and fat are cubed and ground at a very cold temperature with the 6 mm plate of the meat grinder. I have picked the large diameter to decrease the risk of fat dispersing in the meat during grinding.

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The meat is thoroughly mixed with the other ingredients and then stuffed into the soaked sausage casings.

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To help the starter cultures kick off the sausages were hanged for three days at room temperature with humidity as high as possible.

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Then they were transferred to to the cellar for slow drying.

After about a week some white benefitial white mould was appearing on the casings which spread somewhat over time but did not cover the sausages completely.

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Industrially made salami often is inoculated with mould cultures but traditional sausage making usally is done without. It is mandatory, though, to inspect the sausages on a daily basis to check for traces of harmful mould so it can be removed without harm at an early stage.

After four weeks the big day had come. One each of both sausage types was cut, the others were hanged in the cellar again.

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Visually, both from the outside and the inside no significant difference between nitrite and nitrate cured sausages was noticeable. The colour argument might be put to rest here.

From a taste perspective though, there was a a difference indeed. Both sausages had the typical “pur porc” taste but they tasted slightly different. I found the saltpeter cured sausage somewhat fuller and rounder in taste, somehow “meatier” in a way, while the nitrite cured sausage appeared a bit more one-dimensional. The difference was not very big but still well noticeable.

For my personal taste the saltpeter cured sausage had a slight edge. Also my wife agreed after a blind test. So the taste argument should not be dismissed.

{ 2 comments… add one }
  • jude 9th March 2015, 11:44 pm

    Fascinating, as usual. Always wondered about the nitrites, so now I know. Will you leave some a bit longer to see if the flavour differences become more pronounced?

    • oliver 10th March 2015, 5:56 am

      No, I leave them drying simply because they still can be a bit firmer. Weight loss is about 45% so far but I prefer it when they are a bit drier. I doubt the difference will increase by much, maybe unless I wait a few months.

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