Whatever you are intending to smoke, good preparation will give you a better finished product. If smoking fish make sure it is completely cleaned and free from scales. Removing scales prior to salting and smoking allows both the salt and smoke to penetrate more effectively. You can either butterfly your fish with bone in and head on or off or fillet it. With very large fish filleting is recommended.
If smoking meat trim away any loose flesh and remove any visible blood vessels, sinew and cartilage.
Salting or Brining is an essential step in the smoking process. Salt retards unwanted bacterial growth, seasons and enhances flavour plus removes excess the moisture that bacteria need to multiply.
The strength and duration of salting or brining depends on the size and type of food you are intending to smoke. Fish is generally brined in an 80% solution this is a fairly strong brine however due to the high water content in fish it is required to remove sufficient quantity for smoking. This strength of brine also creates a good sticky surface called a (pellicle) once dry, which the smoke will readily stick to.
To calculate the amount of salt required for your desired strength of brine use the following calculation.
A 10% brine solution uses 26g of salt in 1 litre of water. Therefore to calculate the quantity of salt required for an 80% solution, simply multiply 26 by 8 = 208g of salt per 1 litre of water. 1 litre of brine is sufficient for about 1.5 Kg of fish.
Brining times will differ for hot and cold smoking, plus weight and thickness of the product to be smoked. Hot smoke brining is used more for moisture removal and flavour than a preservative. Cold smoking on the other hand requires a larger salt content to stabilize the meat for storage.
As a rule of thumb if you intend to smoke it you should use a nitrite cure. The use of Nitrite cures in addition to salt provides a few useful functions. Although very rare nowadays botulism poisoning is a risk that you run without the use of nitrite cures. In fact the word botulism is derived from the Latin word meaning sausage. Regardless how clean you are in your preparation work, the temperatures that cold smoking and to a degree hot smoking require are within the danger zone for botulism to breed and multiply. Potassium nitrite is extremely effective in preventing botulism and its spores manufacturing toxins. The use of readily available cures that contain potassium nitrite and nitrate give peace of mind and prevent you poisoning your friends and family.
The other useful functions of nitrite cures is fixing colour. The distinctive pink appearance to your see in smoked meat and sausages is due to the potassium nitrite used in the curing process. It also adds flavour.
Pork, fish and poultry all benefit in colour and flavour from adding curing salt, less so with beef and lamb.
Cures come under many brands however they all contain potassium nitrite. In NZ they are sold as pink salt. Not surprisingly they are pink in colour to distinguish them from normal salt. Cures can be obtained from a friendly butcher or butcher supply company.
The two main varieties of available cure are as follows:
Cure No1 (Pink Salt) is 6.25% potassium nitrite in normal salt, used for general smoked sausage and other products that are not going to be stored for long periods of time.
Cure No2 is 6.25% potassium nitrite and 4% potassium nitrate. It is used for dry cured meats and salami. The addition of potassium nitrate is a slow release way of introducing potassium nitrite to the food. It is the Nitrite that kills botulism. The nitrate is converted into nitrite over time by bacterial action prolonging the protection as well as keeping the colour of the food attractive for longer.
General quantity guide for cures:
For sausage including salami the rule of thumb is 0.25% cure by weight. That is 2.5g or ½ a level teaspoon per 1 Kg of raw meat or fish.
For dry cured products such as bacon where the cure is rubbed and pressed into the surface, cure should be added in quantities of 1% by weight. That is 10g or two level teaspoons per 1 Kg raw meat or fish.
For brined products cure should be added at approx 3% that is 30g or 6 level teaspoons per litre of brine solution.