It is only silver eels, which I smoked by this method. Silver eels are eels, which were sexually mature and are on their way to west Atlantic southeast of Bermuda Islands also called Sargasso Sea to spawn at a depth of 7000 meters. They are thick and fat, so they are able to make the long journey of 4000 km. Also read the web page: The biology of the eel.
Just to get into the two eel forms that we have in Denmark, I will briefly mention the following:
During the eel's growing season, it is called "Yellow eels" due to the yellow color of the belly. In this stage distinguish between eels with pointed snout and narrow neck "tip head eel" and eel with broad snout and wide neck "wide head eel". Between these two extremes are, however, smooth transitions. In eels later silver stage the two types differ not much from each other in appearance. Breeding season begins with the eel - both "tip head eel" as "wide head eel" - takes silver on the belly and brass color on the sides. Eyes diameter increases considerably, snout tapers and eels are dark on their backs. During this period, cease the eel to eat, and intestines is dwindling. Eels cannot be captured by either synthetic or natural bait, but in eel-traps. It is the eel which can be smoked, and it might be 10 to 16 years to reach that stage.
Hot wet smoking requires that smokig oven already highly heated before eels hang wet into the oven. I hang eels in when the temperature is 90 °C to 100 °C and the smoke has barely begun. Temperature drops significantly when the "Hat" to be opened 4 to 5 times for 4 to 5 spears with 20 to 25 eel hung in.
I've heard of a tip: Dip eels in hot water (lukewarm about. 40 °C) for a minute and hang them immediately into the smokig oven. This means that Eel-skin becomes soft and flexible, so belly edges stretches and do not cracks. I have now tried it and it works very well especially here in December, when the temperature of eels is very low. They have stayed in the brine at almost freezing point.
But first, prepare the eels for smoking:
Wet salting: I make a strong brine of 15% or 14 °Baume: To 12 liters of cold water add 2,165 kg of fine salt, which corresponds to 20 to 25 large, nice eels of 600 - 800 g piece, which fits my salt jar and smokig oven. The salt must be completely dissolved in the cold water before putting the eels into the brine. If you need a smaller or larger amount of brine, you can use this Excel spreadsheet to calculate the amount of salt.
The eels are slaughtered by sticking them in the back of the head with a short, pointed and sharp knife. Then rub them with salt to mucus disappears.
A new method has been introduced, to put the living eels in a large black plastic bag, tie a solid knot to the bag and place it in the freezer. The bag should preferably lie on something so that there is no direct contact to the bottom and sides. The eels will now go to sleep, just as they usually do in the winter in fresh water. They sleep quietly and die of air deficiency. After a week you can pick up the eels and when they are thawed you can very easily rub the mucus off with a pair of gloves with buds on.
Cut the eel up from head to anus, but be careful not to pierce the gallbladder, remove the intestines with a solid steel spoon and then clean with a stiff brush under cold water. Remember to cut approx. 8 - 10 cm behind the anus to remove the blood string that sits in the tail part. The cleaned and rinsed eels are put in the brine overnight and set cold, max 5 ° C.
Large eels can last for 12 to 18 hours, but small eels only half the time. Remember that the water temperature must NOT exceed 5 °C. There are no problems in November and December, but otherwise you have to use a refrigerator. Small eels range from 300 to 500 grams. Medium eels are from 500 to 800 g. Large eels are from 800 to 1,000 g. Live weight naturally.
The eels are just cleaned with a stiff brush in the brine and then taken up and placed in a new tub of clean, cold water so that excess salt comes off, otherwise the eels can turn white on the skin. They are rinsed well in cold water for blood and mucus residues that the brine has pulled out of the eels.
Then put the ells on skewers. The first skewers I used were hairpin skewers made of 4 mm stainless steel rods, pointed at both ends. The hairpin needle is inserted through the head from the back to the abdomen 2 cm below the pectoral fins and on each side of the spine. It is important not to damage the spine, because then the eel falls down. It happened sometimes, so that's why I made a new concept: Eel suspension - which is much better than the hairpins. So far there are not dropped a single eel down for me.
Now the eels will be smoked
Oven temperature starts as I said at 90 °C to 100 °C. Eels are "cooked", or should we say get tender for 30 to 45 to 60 minutes with the "Hat" slightly open at this high temperature. Water vapor must escape. The eels must open in the belly, so the smoke can penetrate the body from the meat side. It is very important for a good result. Oven temperature is now lowered to 70 °C and eel smoked for 3 to 4 hours at this temperature. After I installed my actuator, I have no problem with keeping a constant temperature of 70 °C throughout. My damper in the jethætten at the top of the "Hat" is not used anymore but is now always fully open, so water vapor can get out of the oven. Cooling time is the time when the eels are in the smokig oven and electric heat is off, the "Hat" is opened and the heat goes below 50 °C. Eels suck the last smoke right into the meat.
Smoking time for eels naturally depends on the size of eel, and the smokig oven used. But common to all the eel is that the temperature inside the meat should be about 67 °C when the eels are smoked in order to avoid the development of bacteria. When I'm using eels from 500 to 800 grams the tender time is 45 minutes, smoking time 3 hours and cooling time 1 hour. Eels from 800 grams up to 1000 grams the tender time are 60 minutes, smoking time 4 hours and cooling time 1 hour. The weight is calculated from live weight.
I have not smoked small eel yet, but the time must of course depend on the weight. Eels below 300 - 400 g are not smoked by me. These eel I fry. I would think that these eels only must have 3 to 4 hours in total.
You can check if the beginning temperature has been correct. Belly opens up nicely, if a suitable temperature. Skins by belly edges detaches itself from the flesh and rolls outwards, if the temperature is too high. If the temperature is too low the belly does not open.
You can test whether the eels are tender, press the back side just below the head. The flesh must yield to turn immediately to swell. A cut in the back can also show whether the meat is white. It shall not be transparent or glassy.
My approach is obviously based on my smokig oven. Oven type and weather - high pressure - low pressure - humidity can affect smoking and tender time. Besides the size of eels, of course.
Weight loss for an eel of 800 grams in weight:
Entrails and gills around 6%
Kidney Blood and mucus around 2%
Fat and fluid loss by smoking around 16%
Total loss approx. 24%
An eel of 800 grams live weighs = 600 grams after smoking.
Losses on filleting: Head, tail, bones and skin is cut away around. 26%
Total weight loss approx. 50% of the eels live weight. So, you smoke an eel at 800 g live weight, you get approx. 400 g eel fillets.
Postscript: After the eels are tender in the first 30 to 45 to 60 minutes at a high temperature, it is important to get water vapor out of the smokig oven. Therefore the "Hat" must have an opening of 1 to 2 cm at the front the first hour. Then "Jethætten" can handle the rest. You may experience some strange recipes with strange times of less than 2 hours. Avoid these eels, they are not good. Eels from 500 grams to 1,000 grams must have from 4 hours to 6 hours with the right temperature and smoke to be really tasty and delicious.
Also try the other recipes
Hot smoking of salmon & trout -- Hot smoking of garfish
Hot smoking of harvest herring -- Hot smoking of mackerel
Hot smoking of cod roe -- Homemade smoking cheese