字幕表 動画を再生する 英語字幕をプリント This episode is brought to you by Nature's Fynd, a fungi-based food company for optimists. Click the link in the description to discover the science behind Nature's Fynd fungi-based foods. [♪ INTRO] Foodies don't mess around with the art and science of cooking. The quality of ingredients and execution of techniques are important, but they're not all that matters. The composition of cookware, from old school classics like cast iron to more newfangled materials like stainless steel, can also make a world of difference. Some famous chefs swear by one of those classic metals for some of their pots and pans— copper. Which historians think humans have been cooking with for thousands of years. But at hundreds of dollars or more for just a piece of cookware, copper is a lot pricier than other materials like stainless steel or aluminum. But some people insist it's well worth the dough. One of the major functions of cookware is thermal conductivity, or the ability to absorb heat from your stovetop and release it into your food. This transfer of energy happens via the movement of free electrons. To keep it really simple, this is because atoms have different amounts of electrons. Copper, for example, has one unpaired electron in its outermost shell. And this unpaired electron gets to wander free in the pure copper. And when you apply heat, the atom closest to the heat source starts vibrating and bumping into the free electrons nearby, transferring the heat. So copper is really effective at thermal conductivity. As a side note, this also applies to its electrical conductivity, which is why we use it in wires. But in the kitchen we often see pans made out of stainless steel or cast iron, which compared to copper, take a long time to heat up in large part because it's an alloy or a mixture of metals. Compared to these alloys copper is 5 times as conductive as cast iron and 25 times as conductive as stainless steel. Because pure copper provides smooth sailing for its electrons. But when you mix copper with other metals to make stainless steel, you're blending atoms of different sizes, forming an irregular alloy framework, which makes the road pretty bumpy for electrons to travel and transfer heat. Another great property of copper is thermal diffusivity. That means that these pans don't only heat up fast, they also spread heat evenly throughout the material. So you don't have to worry about hot and cold spots due to the uneven distribution of heat. In addition to its excellent heat conduction and diffusion, copper is also really responsive to heat. Its electrons get moving right away when you put it over a hot stove, but they also chill really fast when you take the heat source away. So it's great for stuff that needs to heat up fast and also cool down quickly in the same pan, like caramel or delicate sauces. But copper's ready-to-go electrons also make it finicky in some ways. Like, it's prone to oxidation, a process where it loses its electrons and sometimes gains oxygen, forming copper oxides and salts in the process. That's what's going on with the blue-green coating, or patina, that we see on the Statue of Liberty, which has a wrought-iron framework under her thin outer copper skin. And acids speed up this process, they're happy to take electrons from copper. So the issue is, acidic foods like tomatoes can cause these reactions and leach copper into the food, and, over time, that can lead to nasty effects like nausea and diarrhea. To prevent this, some copper pans are lined with more stable metals or alloys like tin or stainless steel to make them safe for contact with those foods and easier to clean. And in some countries, like Canada, it's actually not possible to buy copper pots that aren't lined with a safer metal. But of course, a coated copper pan takes a hit on conductivity depending on the coating material and thickness. Now, some chefs argue that actually a thicker steel or aluminum pan can do the trick as well as copper. And that has to do with the capacity of different metals to store heat per unit of mass. Stainless steel, for instance, requires about 25% more energy to heat up than the same mass of copper and is almost as dense as copper. So if you're willing to wait for your cookware to heat up, a moderately more thick stainless steel pan can pack a comparable amount of heat. And then there's silver, the only cookware material that beats copper at conductivity-- but not by much. Compared to copper, silver has a bit of an edge because it has one more electron shell, so its free electrons are a little more free to move around and transfer heat. But silver pans are obviously way more expensive they're known as the chef's version of a Rolex. So, the answer to whether you need a copper pot depends on... ...what your needs are. Copper has its perks, but you can totally go to town in the kitchen with an alloy like stainless steel, or another material. But now you know how electrons move in different pans and heat up its contents, so hooray for informed decision-making! Or if all this chemistry talk just has you beat, you can always consider outsourcing the electron-vibing and just order some takeout. OR you can use whatever kind of pot you prefer to cook a protein-rich vegan meal with Nature's Fynd. From a microbe first discovered by NASA-funded research, Nature's Fynd uses fermentation to grow nutritional fungi protein that's more sustainable than traditional agriculture. I really enjoyed getting to try Nature's Fynd meatless breakfast patties. It's honestly pretty impressive what they're able to accomplish with fungi. You can click on the link in the description to check out the science behind their fungi-based foods, or follow their story over on Instagram! [♪ OUTRO]