CURING

In its simplest form the word ‘curing’ means ‘saving’ or ‘preserving’ meat and the definition covers preservation processes such as: drying, salting and smoking. When applied to home made meat products, the term ‘curing’ usually means ‘preserved with salt and nitrite.’ When this term is applied to products made commercially it will mean that meats are prepared with salt, nitrite, ascorbates, erythorbates and dozens more chemicals that are pumped into the meat. Meat cured only with salt, will have a better flavor but will also develop an objectionable dark colour.

Factors that influence curing:

The size of the meat - the larger meat the longer curing time.

Temperature - higher temperature, faster curing.

Moisture content of the meat.

Salt concentration of dry mixture or wet curing solution-higher salt concentration, faster curing.

Amount of fat-more fat in meat, slower curing.

pH - a measure of the acid or alkaline level of the meat. (Lower pH-faster curing).

The amount of Nitrate and reducing bacteria present in the meat.

Curing Temperatures

The curing temperature should be between 36-40° F (2-5° C) which falls within the range of a common refrigerator. Lower than 36° F (2° C) temperature may slow down the curing process or even halt it. Commercial producers can cure at lower temperatures because they add chemicals for that purpose. There is a temperature that can not be crossed when curing and this is when meat freezes at about 28° F (-2° C). Higher than normal temperatures speed up the curing process but increase the possibility of spoilage. This is a balancing act where we walk a line between the cure and the bacteria that want to spoil meat. The temperature of 50° F (10° C) is the point that separates two forces: below that temperature we keep bacteria in check, above 50° F (10° C) bacteria forces win and start spoiling the meat.

Meats were traditionally cured with Nitrate. Before Nitrate can release nitrite (the real curing agent) it has to react with bacteria that have to be present in the meat. Putting Nitrate into a refrigerator kept solution (below 40° F) will inhibit the development of bacteria and they may not be able to react with Nitrate. On the other hand sodium nitrite works well at refrigerator temperatures. When used with Nitrates/nitrites, salt is an incredibly effective preserving combination. There has not been even one documented incident of food poisoning of a meat cured with salt and Nitrates.

People in the Far East, Africa, South America and even Europe are still curing meats at higher than normal temperatures without getting sick. That does not mean that we recommend it, but if someone in Canada shoots a 1600 lbs (726 kg) Moose or a 1700 lbs (780 kg) Kodiak Bear he has to do something with all this meat. He is not going to spend 5,000 dollars on a walk-in cooler, is he? These are exceptional cases when curing can be performed at higher temperatures. After the Second World War, ended most people in Europe neither had refrigerators nor meat thermometers, but were curing meats with Nitrate and making hams and sausages all the same.

Because of primitive conditions the curing temperatures were often higher than those recommended today but any growth of C. botulinum bacteria was prevented by the use of salt and Nitrates.

They also predominantly used potassium Nitrate which works best at temperatures of 46-50° F (8-10° C) and those were the temperatures of basement cellars. There was not much concern about longer shelf life as the product was consumed as fast as it was made. Salt and nitrite will stop Cl. botulinum spores from developing into toxins, even at those higher curing temperatures. Due to increased bacteria growth at those higher curing temperatures the shelf life of a product would be decreased. Remember when handling meats, the lower the temperatures the slower the growth of bacteria and the longer life of the product. Extending the shelf life of the product is crucial for commercial meat plants as the product can stay on the shelf longer and has better chances of being sold. Curing is a more complicated process than salting. In addition to physical reactions like diffusion and water binding, we have additional complex chemical and biochemical reactions that influence the flavor and colour of the meat.

What Will Happen if Too Little or Too Much Cure is Added?

With not enough cure, the colour might suffer with some loss of cured flavor too. FSIS regulations dictate the maximum allowed nitrite limits and there are no limits for the lower levels. It has been accepted that a minimum of 40-50 ppm of nitrite is needed for any meaningful curing. Too much cure will not be absorbed by the meat and will be eaten by a consumer.

What Will Happen if the Curing Time is Shorter or Longer?

If the curing time is too short, some areas of meat (inside or under heavy layers of fat) will exhibit an uneven colour which might be noticeable when slicing a large piece of meat. It will not show in sausages which are filled with ground meat, although the colour may be weaker. If curing time is longer by a few days, nothing will happen providing the cured meat is held under refrigeration. You don’t want to cure bone-in meats longer than 30-45 days as they may develop bone sour even when kept at low temperatures. Taste your meats at the end of curing. You can always cure them longer in a heavier brine (to increase salt content) or soak them in cold water (to lower salt content).

Cured Meat Colour

Fresh Meat Colour

The colour of fresh raw meat is determined largely by the amount of myoglobin a particular animal carries. Meat colour is determined largely by the amount of myoglobin (protein) a particular animal carries. The more myoglobin the darker the meat, that simple. The amount of myoglobin present in meat increases with the age of the animal. This colour is pretty much fixed and there is not much we can do about it unless we mix different meats together.

Different parts of the same animal, take the turkey for example, will display a different colour of meat. To some extent oxygen use can be related to the animal’s general level of activity; muscles that are exercised frequently such as the legs need more oxygen. Muscles that are exercised frequently such as legs need more oxygen. As a result they develop more myoglobin and a darker colour unlike the breast which is white due to little exercise.

Pork loin is light pink in colour as this muscle does not work much, however, leg muscles excercise a lot and are light red. Heart of any animal is dark red as it works continuously.

Fish float in water and need less muscle energy to support their skeletons. Most fish meat is white, with some red meat around the fins, tail, and the more active parts of the fish which are used for swimming. Most fish don’t have myoglobin at all. There are some antarctic cold water fish that have myoglobin, but it is confined to the hearts only (flesh of the fish remains white but the heart is of a rosy colour). As most of the fish don’t have myoglobin the meat is not going to be pink and that explains why very few fish recipes include cure.

The red colour of some fish, such as salmon and trout, is due to astaxanthin, a naturally occurring pigment in the crustaceans they eat. Most salmon we buy is farm raised and as it is fed a prepared commercial diet that even includes antibiotics, its meat is anything but pink. The only reason that farmed raised salmon flesh is pink is that canthaxanthin (colourant) is added to the food the fish eats.

Cured Meat Colour

The colour of cured meat is pink and is due to the reaction between nitrite and myoglobin. The colour can vary from light pink to light red and depends on the amount of myoglobin a particular meat cut contains and the amount of nitrite the amount of nitrite added and the cooking temperature.

Chicken breast works very little so its meat contains a little myoglobin. As a result the curing process is weak and the cured colour is light pink. Chicken legs, thighs and neck work continuously so the meat is darker and the curing colour will be light red.

Pork can vary from light pink (loin) to light red (ham). Pork belly or jowls have layers of pink meat separated by layers of fat.

Beef is darker as a cow walk a lot and lives longer.

Game meat is the darkest as wild animals are always on the move. Wild boar meat is much darker than that of a domestic pig.

If an insufficient amount of Nitrate/nitrite is added to the meat or the curing time is too short, the cured color will suffer. This may be less noticeable in sausages where the meat is ground and stuffed but if we slice a larger piece like a ham, the poorly developed color will be easily noticeable. Some sections may be gray, some may be pink and the meat will not look appetizing. To check your cured meats, take a sample, cut across it and look for uniform color. About 50 ppm (parts per million) of nitrite is needed for any meaningful curing. Some of it will react with myoglobin and will fix the color, some of it will go into other complex biochemical reactions with meat that develop a characteristic cured meat flavor. If we stay within Food and Drug Administration guidelines (1 oz. Cure #1 per 25 lbs of meat - about 1 level teaspoon of Cure #1 for 5 lbs of meat) we are applying 156 ppm of nitrite which is enough and safe at the same time.

Curing Fat

Pork back fat has no myoglobin so it makes a little sense to cure it with sodium nitrite. Nitrite will not react with fat and the customer will have to eat it. Pork back fat is cured with salt only and after 3 weeks becomes soft and delicious to eat. Cured back fat was always popular in Germany, Poland and Russia, however, take note that such a back fat was about 3-4 inches thick. It will be very hard to find a pig nowadays that could offer such a thick back fat.

Fat trimmings used for sausages are salted only.

Pork bellies and jowls consist of layers of meat and fat. They are cured with salt and sodium nitrite like a regular meat, however, the amount of sodium nitrite can be slightly decreased due to the large amount of fat those cuts contain.

Colour of Cooked Meat

The colour of cooked meat varies from grayish brown for beef and grey-white for pork and is due to denaturation (cooking) of myoglobin. The red colour usually disappears in poultry at 152° F (67° C), in pork at 158° F (70° C) and in beef at 167° F (75° C).

Cured meat will develop its true cured colour only after submitted to cooking (boiling, steaming, baking) at 140-160° F (60-71° C). The best colour is attained at 161° F (72° C).

In the following photos all meats (fresh and cured) were cooked. As it can be seen the cured meat becomes red after cooking. Cooked fresh pork leg will becomes grey, for example roasted leg of pork. However, when cured with sodium nitrite (cure 1), it becomes pink ham.

Curing With Nitrates/Nitrites

Meat cured only with salt, will have a better flavor but will also develop an objectionable dark colour. Adding nitrites to meat will improve flavor, prevent food poisoning, tenderize the meat, and develop the pink colour widely known and associated with smoked meats. In the past we used potassium Nitrate exclusively because its derivative, sodium nitrite was not discovered yet. Sodium Nitrate (NaNO3) does not cure meat directly and initially not much happens when it is added to meat. After a while micrococci bacteria which are present in meat, start to react with Nitrate and create sodium nitrite (NaNO2) that will start the curing process. If those bacteria are not present in sufficient numbers the curing process may be inhibited.

Curing with Nitrate

The reactions that occur are the following:

KNO3 potassium Nitrate → KNO2 nitrite (action of bacteria)

KNO2 → HNO2 nitrous acid (in acid medium, pH 5.2 - 5.7)

HNO2 → NO nitric oxide

NO → myoglobin → nitrosomyoglobin (pink color)

Potassium Nitrate worked wonderfully at 4-8°C (40-46°F) which was fine as refrigeration was not very common yet. If the temperatures dropped below 4°C (40°F) the bacteria that was needed to force Nitrate into releasing nitrite would become lethargic and the curing would stop. Potassium Nitrate was a slow working agent and the meat for sausages had to be cured for 72-96 hours.

The use of Nitrate is going out of fashion because it is difficult to control the curing process. By adding sodium nitrite directly to meat, we eliminate the risk of having an insufficient number of bacteria and we can cure meats faster and at lower temperatures. Sodium nitrite does not depend on bacteria, it works immediately and at refrigerator temperatures 2-4° C (35-40°F). At higher temperatures it will work even faster. About 15% of sodium nitrite reacts with myoglobin (colour) and about 50% reacts with proteins and fats (flavor).

Curing Accelerators

The time required to develop a cured colour may be shortened with the use of cure accelerators. Ascorbic acid (vitamin C), erythorbic acid, or their derivatives, sodium ascorbate and sodium erythorbate speed up the chemical conversion of nitrite to nitric oxide which reacts with meat myoglobin and creates nitrosomyoglobin (pink colour). They also deplete levels of meat oxygen which prevents the fading colour of the cured meat in the presence of light and oxygen. Commercial producers perform curing in one step by injecting meats with a curing solution and then bouncing meat inside of the tumbler machine to evenly distribute solution inside. There is not enough time to develop true cured colour and the cure accelerators are introduced intro curing solution. Now the meats can be cured fast and the true cured colour will develop.

Best Meats for Curing

Pork - best colour, taste and flavor

Beef - significant loss of protein and minerals

Lamb - little improvement

Veal - little improvement

Poultry - good

Fish - good, the looks and flavor of smoked fish is greatly influenced by curing

American Cures

Cure #1 (also known as Instacure #1, Prague Powder #1 or Pink Cure #1)For any aspiring sausage maker it is a necessity to understand and know how to apply Cure #1 and Cure #2, as those two cures are used worldwide though under different names and with different proportions of nitrates and salt. Cure #1 is a mixture of 1 oz of sodium nitrite (6.25%) to 1 lb of salt. It must be used to cure all meats that will require smoking at low temperatures. It may be used to cure meats for fresh sausages (optional).

Cure #2 (also known as Instacure #2, Prague Powder #2 or Pink Cure #2)Cure #2 is a mixture of 1 oz of sodium nitrite (6.25%) along with 0.64 oz of sodium Nitrate (4%) to 1 lb of salt. It can be compared to the time-releasing capsules used for treating colds. It must be used with any products that do not require cooking, smoking or refrigeration and is mainly used for products that will be air cured for a long time like country ham, salami, pepperoni, and other dry sausages. Both Cure #1 and Cure #2 contain a small amount of FDA approved red coloring agent that gives them a slight pink color thus eliminating any possible confusion with common salt and that is why they are sometimes called “pink“ curing salts. Cure #1 is not interchangeable with Cure #2 and vice versa.

Our commonly available cures contain both nitrite and Nitrate.

European Cures

There are different cures in European countries, for example in Poland a commonly used cure goes by the name “Peklosól” and contains 0.6% of Sodium Nitrite to salt. No colouring agent is added and it is white in colour. In European cures such a low nitrite percentage in salt is self-regulating and it is almost impossible to apply too much nitrite to meat, as the latter will taste too salty. Following a recipe you could replace salt with peklosól altogether and the established nitrite limits will be preserved. This isn’t the case with American Cure #1, that contains much more nitrite in it (6.5%) and we have to colour it pink to avoid the danger of mistakes and poisoning.

How to Apply Cures

Well, there are two approaches:

Like an amateur - collecting hundreds of recipes and relying blindly on each of them. You lose a recipe and you don’t know what to do. And how do you know they contain the right amount of cure?

Like a professional - taking matters in your own hands and applying cures according to the requirements.

In case you want to be the professional, we show some useful data Cure #1 was developed in such a way that if we add 4 ounces of Cure #1 to 100 pounds of meat, the quantity of nitrite added to meat will conform to the legal limits (156 ppm) .

That corresponds to 1 oz. (28.35 g) of Cure #1 for each 25 lbs. (11.33 kg) of meat or 0.2 oz. (5.66 g) per 5 lbs. (2.26 kg) of meat.

Cured dry products -

country ham, country style pork shoulder, prosciutto, etc. These products are prepared from a single piece of meat and the curing ingredients are rubbed into the surface of the meat several times during the curing period. Nitrite is applied to the surface of the meat or poultry as part of a cure mixture.

To cure meat for sausages and to stay within 156 ppm nitrite limit we have to apply no more than 1 oz of Cure #1 for each 25 lbs of meat. To dry cure 25 lbs of pork butts and to stay within 625 nitrite limits we need 4 times more of Cure #1, in our case 4 ounces. Keep in mind that when you add Cure #1 (there is 93.75% salt in it) you are adding extra salt to your meat and you may re-adjust your recipe.

The reason that there are much higher allowable nitrite limits for dry cured products is that nitrite dissipates rapidly in time and the dry cured products are air dried for a long time. Those higher limits guarantee a steady supply of nitrite.

Immersed, Pumped and Massaged Products

such as hams, poultry breasts, corned beef. Here, it is much harder to come up with a universal formula as there are so many variables that have to be determined first. The main factor is to determine % pump when injecting the meat with a syringe or % pick-up when immersing meat in a curing solution. We will calculate the formula for 1 gallon of water, Cure #1 and 10% pick-up gain. Then the formula can be multiplied or divided to accommodate different amounts of meat. 10% pump or 10% pick-up mean that the cured meat should absorb 10% of the brine in relation to its original weight. For immersion, pumped or massaged products, the maximum in-going nitrite limit is 200 ppm and that corresponds to adding 4.2 oz of Cure #1 to 1 gallon of water.

This is a very small amount of brine and if you want to cure a large turkey you will need to increase the volume. Just multiply it by a factor of 4 and you will have 4 gallons of water and 1.08 lbs. of Cure #1. The following is the safe formula for immersed products and very easy to measure: 5 gallons of water, 1 lb. of Cure #1. In the above formula at 10% pick-up the nitrite limit is 150 ppm which is plenty. Keep in mind that adding 1 lb. of Cure #1 to 5 gallons of water will give you 4.2% salt by weight and that corresponds to only 16 degrees brine (slightly higher than sea water). If we add an additional 2 lbs. of salt we will get: 5 gallons of water, 1 lb. of Cure #1, 2 lbs. of salt and that will give us a 25 degree solution which is great for poultry.

Useful Information

If it can’t be cured don’t smoke it

When curing is completed it is advisable to test the meat for colour and saltiness by cutting a tiny piece and looking at the cross cut section. It should have a uniform pink colour. In case it is too salty, place the meat in cold water in refrigerator for 12 hours and taste again. It is much easier to fix the problem now than to eat sausage later with tears in our eyes.

Add an extra 24 hours of curing time if needed.

About 1 level teaspoon of Instacure #1 is needed for 5 lbs of meat ( there are 5-6 teaspoons to 1 oz of cure) or 2.5 grams of cure for 1 kilogram of meat.

Keep separately different types of meat (lean and fat pork, beef)) as some of them might go again to the grinder to be ground through a different plate.

Cured ground meat will be drier and harder to stuff into casings because of the action of the salt. It is advisable to dice the meat or grind it through a big a plate and after curing regrind it with a proper size plate before stuffing. If the meat will not be ground again, re-mix it well by hand.

The two premixed cures, Instacure #1, and Instacure #2, are not interchangeable.

Containers for curing are to be made of stainless steel, food grade plastics or stone. Nitrates react with aluminum and it should not be used for curing.

Add sugar only when curing at refrigerator temperature 38 – 40° F (4 –5° C), otherwise fermentation might occur and will spoil the meat.

Cure mixtures and curing solutions do not work on frozen meat. Meat must be first thawed.

Dry curing is the preferred method to cure meat for production of sausages.

When rubbing ham make sure the cure is rubbed into the aitch bone joint and hock end of the ham.

Sodium nitrite is used where curing time will be short : sausages, small pieces of meat.

Sodium nitrate is used in production of meats that will be cured for at least 4 weeks - large hams or dry sausages.

A characteristic quality of fresh cured meat is its grey colour which comes on minutes after adding nitrite to the meat.

The cured meat will achieve its characteristic pink colour when heated to 130° F (54° C) or higher. Best curing colour achieved by cooking cured meat to 161° F ( 72° C) inside temperature.

Sugar counters the harshness of the salt, improving the flavor. Normally we add 3% sugar in the salt (that means that for 100 kg of the mix – we have 97 kg salt and 3 kg sugar).

When using sodium ascorbate or sodium erythorbate in curing solution, it should be used within 24 hours because their reaction with nitrite will lower the nitrite level of the solution and its effectiveness.

Phosphates should be used only with wet cure. They increase the water holding capacities of cured products.

The length of curing (dry cure method) is seven days per inch of thickness of meat.

Adding too much nitrates/nitrites (crossing upper limits) to the dry mixture or wet curing solution can impart a bitter and strong curing taste to the meat.

50 ppm of sodium nitrite is accepted as the minimum for the development of the proper colour of the meat.

Modern-day cured meats at retail have a residual nitrite content of about 10 ppm.