Flash chilling is very simple. Just make sure you have a fairly large ice bath (ice and water that is at least 50% ice) and put the meat immediately from the heated bath into the ice bath. This will rapidly chill the meat prior to refrigeration. Make sure you leave the meat in the ice bath long enough for it to chill to the center if it's a thick cut or a roast.
1 How big should I expect the swings in my home fridge to be with normal usage?
The mild swings from opening and closing your refrigerator door a couple times a day aren't going to really make big difference. Just make sure you don't leave the door open for extended periods of time.
2 If I have a second fridge and the door rarely opens, what will the temperature swings be there?
There are a lot of things that influence the temperature of a refridgerator besides opening and closing the door. A refrigerator goes through cycles for chilling (and for defrosting) etc where the temperature varies. Some brands of refridgerators (i.e. Samsung) have separate cooling systems for the freezer and fridge portions so freezer defrost cycles do not cause swings in temperature in the fridge section.
Also, an empty refrigerator loses a lot more heat than a full refrigerator when the door is open. Storing plastic bottles of water or cans of soda and beer on empty shelves will actually make the temperature more constant over time since they retain more heat (or "cold") than air. Of course, if you turn a fridge into a beer-fridge, chances are that the door is gonna get opened a lot more.
3 Since the botulism concern is due to the vacuum, am I correct in thinking that this concern will disappear if I remove the meat from the vacuum to store it? Obviously, this approach would reintroduce all the normal safety concerns with storing cooked meat.
Sous-vide cooking should pasteurize the meat if it was cooked long enough and kill most . Keeping the pastuerized food that is sealed at a controlled temperature is going to preserve it for much longer than breaking open the seal and allowing any pathogens in before keeping it at the same temperature.
The most important thing is to follow the established safety charts for cooking times, temperatures, using correct flash chilling and then following the safety charts for storage temperatures and duration as well.
The best way to test if it's done is to use an instant-read thermometer. Slide it into the thickest part, away from any bones. I like to lift up the meat with tongs and poke it into the edge, all the way to the center. You're looking for about 135-140F for medium rare; take it off a little early if anything because the temperature will go up a bit once it's off the heat. Let it rest for ten minutes or so before digging in to let the juices re-distribute.
I don't like using nonstick for steak, or olive oil. Neither does well at high heats, which is what you need to cook off moisture at the surface and get a nice browned outside before the inside gets overcooked. Cast iron and steel (stainless or carbon) both work very well in my experience. For fat, use a high smoke point oil like safflower oil, or clarified butter.
Best Answer
This cup is not painted, but enameled, which means it is covered with a thin layer of molten glass (emaille).
As vitreous enamel is basically glass, it brings the same chemical and physical properties: chemically resistant, durable, scratch-resistant, smooth and long-lasting.
Enameled cookware is very safe, even at high temperatures (oven-proof), and easy to clean. The main weakness it the fact that the coating chips easily if the pot is dropped, but modern cookware is relatively resistant compared to older models. Some well-known manufacturers produce pots and pans with enamel, random examples are Le Creuset, Staub, Le Chasseur and others.
The kind of cup you have was quite common in farmers' households world wide a century or two ago and is still available in eastern European countries and the Balkans. It has fallen out of favour a bit in the West over the last decades but the recent "retro" trend has enameled goods (including tins, jugs and bowls) appear again, it seems. Note that campers, hikers and hunters always loved them for their versatility and sturdyness.
So don't hesitate to use your enameled cup on the stove, it was made for that use.