In part one we looked at the process of turning a herring into a kipper. We looked at the preparation of the fish, splitting the fish through it's back and the method used to brine the fish ready for the smoker. In this part of the blog we will discuss the smoking process, what's happening to the fish while it is being smoked and some of the finer points of smoking. In particular we will look at the cold smoking process, what this means and how to manage the process. First of all we will discuss the benefits of hanging your fish or laying them flat.
Well, we've brined and dried the herrings and were ready to give them some time in the smoke. The smoking process will transform the humble herring into the wonderful kipper. We will be cold smoking the herring which means we will be using the qualities of the smoke to add flavour and utilise the ability for smoke to preserve. In this day and age we tend to rely on refrigeration to ensure the fish is safe but back in the day the smoking process was the primary means of preserving the fish. There is another process at work here while the fish is being smoked and thats drying. As the herrings are turning into kippers they will continue to dry out. As they dry out it becomes more difficult for bacteria to grow.
The key part of cold smoking is the control of temperature. Unlike hot smoking which is essentially cooking and adding flavour with smoke, cold smoking uses the smoke without the heat. For many this can be a little problematic. Separating the heat of combustion from the products of combustion can be a little difficult. There are methods that the smoker can adopt to remove heat. The simplest is to use a smoke generator that limits the amount of heat generated to the absolute minimum. Contrary to popular belief, you don't need copious amounts of smoke to get great flavour. Anyone who's stood next to a bonfire will attest to how powerful smoke can be in adding aroma to your clothes.
If you don't have the luxury of a smoke generator which limits the heat output you'll need to look at other methods of separating out the heat and smoke. The simplest method of achieving this separation is to physically separate the smoke generating from the food smoking, slinking them together with a pipe. Tis technique will allow the heat in the smoke to dissipate as it travels along the pipe into the smoking chamber. The aime here is to remove sufficient heat in the smoke to ensure the temperature in the smoking chamber to remain well below 30C. Keeping the temperature at this low level will prevent the kipper from drying out too much and also prevent it from cooking which will ruin what you are trying to achieve. Personally I like to maintain a temperature below 20C. At this temperature the fish will continue to loose moisture steadily while the smoke does it's thing.
Kippers will taste great with as little as four hours of cold smoke. After four hours though they will not really develop much colour and their smokey flavour will be on the light side. Now, depending on your personal taste you can smoke for up to twenty four hours to develop a really deep colour and rich flavour. It's intesting to note that as the kipper continues to dry whilst in the smoker the ratio between the oil and water in the flesh changes significantly to give the kipper a lovely glossy appearance. One should be aiming for between 15% to 20% weight loss in total from both the brining and smoking process when compared against the weight of the herring before brining.
There is a debate as to whether hanging herrings or laying them on racks is the best method. Personally I've found no discernible differences between the two methods in terms of quality but its true to say that hanging will improve the capacity of your smoker.
If you would like to learn how to make kippers why not sign up for one of my food smoking courses. These courses run thought the year and cover all aspects of food smoking and are suitable for the complete beginner or the restaurant chef looking to improve their skills in this artisan craft. Visit www.coldsmoking.co.uk for more details. Good luck and happy smoking.