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How Smoke Preserves Food: A Guide To Cold Smoking



How Smoke Preserves Food:

A Guide to Cold Smoking

  Smoke preserves food, both physically and chemically, and it tastes amazing! Although, most of us already knew the taste part, and so did ancient humans. There is evidence of neolithic people smoking the animals they hunted, probably with simple setups like a tripod of sticks over an open fire, but compared to other preservation methods smoking was probably not the most effective. Salt curing is better for preservation. Which is why safe smoking will usually start with a short salt cure. Salting and smoking both work best if you start with thin cuts of meat. It’s typically recommended to use about 1/4 inch cuts, much like slices of beef jerky. Historically, smoke is most useful for preserving meat given meat’s high pathogen load, although we also smoke everything from cheese and salmon to spices and nuts. Nowadays we smoke mostly to imbue the smoke flavor since we have the luxury of modern technology to help with preservation. After a 24 period of salt curing osmosis will already have noticeably kicked in and you can see how much water comes out of the meat. At this point the meat will be very stiff. Microorganisms love water and hate salt, so with a simple cure it’s already halfway preserved now all we need is smoke!
Adding Smoke:

While smoking the cut of meat remember that only smoke is being added and it is not cooking it. The main goal of this step is to dry out the mead and add some extra flavor. Drying is certainly the oldest food preservation method, but we’re going for preservation and taste. Neolithic people noticed that incorporating smoke into their cooking made the food taste better and last longer than food simply dried out in the sun. Back then they had to be creative to keep the smoke on the food. Nowadays we enjoy the luxury of cookers that hold the smoke for us to retain all the good flavor inside instead of escaping into the open air. Smoke is a product of incomplete combustion, when wood burns thoroughly all that is left is carbon dioxide and water. Thus, a roaring hot fire will produce less smoke proportionally because more organic chemicals that comprise smoke are being burned. a low smoldering fire will burn less of it’s own smoke, and that’s exactly what we are looking for! These chemicals in the smoke help to preserve the food.

Types of Smoke:

There are two basic kinds of smoking:  Hot smoking and Cold smoking. Cold smoking is used for preservation and results in beef jerky, smoked cheese, smoked salmon, or simply adding flavor before you cook a cut of meat. Hot smoking results in more American style Barbecue – hot smoking in a moist environment. American style barbecue is delicious, but it is not preserved. That is why it tastes best right off the smoker. When food is smoked hundreds of flavor-bearing chemicals in that smoke are deposited onto the surface of the food. The most important among these chemicals are guaiacol and syringol, both of which dissolve readily in fats but are detected by our senses in slightly different ways—we experience syringol as an aroma and guaiacol as a flavor. Unfortunately, both these chemicals have high vapor pressures, so they evaporate easily. What that means is that the ribs you eat today will have more of the good-tasting chemicals—and thus the complexity—than they’ll have when reheated in the oven tomorrow. On the other hand, cold smoking especially in cheese takes time to mellow out and tastes best when left alone in the refrigerator for 1-2 weeks. Hot smoking is solely for flavor and cooking and is typically over 160F or 70C. At this temperature the connective tissue collagen starts to break down and meat basically brazes in its own internal water. As long as the smoker is kept sealed it will retain the humidity, and before the meat dries out, it will be fall apart tender. Hot smoking in a dry environment might also dry out the outer layer of meat too quickly. This is known as case hardening, and this is very bad. when you get case hardening you basically trap moisture on the inside of the food. The outside will look nice and dry, but the inside is still we which allows for microbial growth. Cold smoking is generally defined as smoking under 100F or 38C, and warmer than that and fat starts to melt out and render.


The Science:

Cold smoking mainly preserves food by drying it, but it does more than that. How? you can kill some bacteria even with liquid smoke. Now in the smoking world, bringing up or using liquid smoke is pure blasphemy, but in this sense it is purely for science. Liquid smoke is not an artificial flavoring, as I believed it was before studying for this article, but it is smoke condensed down to a water-based liquid. Scientists attribute this effect to two classes of chemicals found in wood smoke, Phenols and Carbonyls. Phenols disrupt the cell membranes of bacteria, causing them to leak and die, much like popping a balloon. Carbonyls bond easily with amino acids proteins, so when the carbonyl enters the bacteria they effectively deactivate enzymes that the germs need to function. They basically disrupt the bacteria’s food supply. Listeria is rather resistant to smoke and can survive salt and acid to a point, and unlike any other food borne pathogen, listeria can survive at refrigerator temperatures and will multiply rapidly. The only surefire way to kill listeria in food is to cook it. The good news is that listeria isn’t dangerous to a normal healthy adult, unless you are pregnant. If you are pregnant,  you are far more likely to get sick from listeria because your immune system is going haywire, and once listeria is running wild in your body, they are particularly good at passing the placental barrier. That is why if you are pregnant, doctors tell you to avoid cured meats and raw dairy products, and even some raw vegetables like bean sprouts.

Cold smoking can most certainly be done at home, and there are plenty of people that do it correctly and expertly. But if it is your first time, please make sure to do your research to make sure that you are keeping yourself, your family, friends, and those that you plan on eating your cold smoked food safe. Make sure that the recipe that you are using has all safety measures in mind, not just a list of ingredients from your buddy at the bar or someone from a local barbecue competition. You must also make sure to be precise with the amount of salt or preservatives that you use in your cures. At the end of the day, we at Smoke Daddy want to make sure that everyone are safe and informed on what you should and should not be doing with your smoker.





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