© Denzil Green
A Blowtorch is like a portable broiler (aka grill in the UK) or salamander, to heat the tops of food items. In Japan, they are used at small tofu stands to make Yakidofu, though a few stands still grill the tofu the old way over charcoal.
A Blowtorch can brown one area of food, without heating the rest of the food, or the dish the food is in or on. The classic use is for caramelizing the top on Crème Brûlée. In restaurants, this would most likely be done in a salamander.
The length and width of the flame is adjustable.
You can use Blowtorches designed for kitchen use, or larger ones from hardware stores. In fact, because the small ones designated for kitchen use tend to use butane cannisters for fuel, some people prefer the hardware store ones, which use propane, because they feel that butane is a "dirtier-burning" fuel than propane
In any event, the small kitchen Blowtorches don't hold a lot of fuel, so you might want to reserve their use for things you really want it for, rather than trying to find other applications for them (see other uses below.) Many kitchen Blowtorches are self-igniting, and some have easy on / off buttons that you just activate via your thumb. Many will have safety locks so that you can't accidentally turn it on while handling it. If you get a kitchen Blowtorch, it is very compact and easy to store. Some kitchen ones, though, come with stands should you choose to display them.
Those who like to use a torch regularly, and for many things, tend to be the ones who go with the large hardware-store ones, sometimes referred to as a "plumbing" propane type. They use refill bottles that an be got anywhere, are cheap, and are large enough that you're not going to be running out of fuel all the time, One popular brand name in North America is Bernzomatic. Restaurants, when they're not using a salamander, will use the plumbing type of Blowtorch. The size of these torches makes them a bit daunting, but they can be used for many other things around the house, from actual plumbing chores to burning out weeds between cracks in stones and sidewalks. With some plumbing ones, the flame may go out when it is pointed straight down: you'll need to tilt it a little.
Whatever kind of Blowtorch you get, be sure to read and follow the manufacturer's directions carefully. Even if you don't use your Blowtorch very often, you may be able to justify one on the basis that it can be just plain fun to use.
Blowtorches can be used to:
- Brown meringues, especially on dishes such as a Baked Alaska
- Heat the sides of cheesecake pans for easier removal
- Peel tomatoes
- Char the skin of peppers for easy peeling
- Char the flesh of eggplant to give it a smoky taste;
- Melt cheese;
- Melt the cheese on top of French Onion Soup without having to turn the whole oven on;
- Roast chiles.
For many of these applications, though, it really only makes sense to use a Blowtorch if you are doing these things in small quantities, such as roasting 1 or 2 chiles. If you're doing anything in any quantity at all, you'll likely want to turn to other methods (e.g. blanching a dozen tomatoes for a minute or two in a large pot of boiling water, then peeling them, tossing 5 pound of eggplant on a grill for a smoky taste, etc.)
It is best to go slowly, and do one area at a time. Taking Crème Brûlée as an example, you need to keep the flame quite close to the sugar, and move it about slowly. The sugar should bubble up, then brown before you move on.
To caramelize sugar on fresh-fruit pieces, peel and slice the fruit, lay it out on a baking sheet, sprinkle a thin layer of white sugar on each piece, then apply the torch. This kind of fruit can be used as a topping or garnish for many desserts, such as opened-faced custard pies, etc.
Some people are concerned about applying flame to small dishes that might have been made ahead and chilled in the fridge. If you're concerned, use Corningware or Pyrex ramekins.