Tuesday, June 15, 2010

Cooking: The Blanche

Cooking foods does lots of great things for us. First off it often improves the taste, which is always nice. Cooking can also liberate more nutrients providing more power for our bodies. Proper cooking can also kill off surface bacteria. 

I'll focus on the last one for this post: Killing surface bacteria.
Generally speaking most of the food we have is pretty darn clean, but people walking around the produce section can and do cough and sneeze. A simple wash will wash off most of these germs but if you need to be sure your vegetables are germ free you can employ the blanche

Blanching food does several things. It will kill surface bacteria, it will liberate cellular oxygen allowing the base color of the food to be more easily seen and it will loosen the skins on certain foods.

You already know that bring water to a boil will kill the germs in the water, but did you realize that boil water will kill the germs on the outside of the things put into the water? Nobody ever mentions it but this is actually very important. 

Have you ever noticed how bright the colors are on those vegetable trays you can get at the store but the raw vegetables you get from the produce section are rather lackluster looking at the same time? The reason is that raw foods still have lots of oxygen bound up in them. By blanching foods the heat will cause the oxygen to liberate from the cells of the food allowing the colors underneath to shine through.  Overcooking will cause the colors and the cellular structure of the food to breakdown resulting in an ugly gray goo. We're going to prevent that with an ice-water shock bath. This works best on foods like broccoli, beans, carrots and celery, you know, the foods you usually see on a veggie tray.

Blanching will loosen the skins on certain foods, like tomatoes and peaches, for easier processing. Cooking tends to weaken cellular structures, since a blanche is so quick only the very outside of the food will cook, that makes skinning the food much easier and less wasteful. This is most often used on foods like tomatoes and peaches. This is the first step to making Tomato Concassé, which is the foundation of tomato sauce, or peach cobbler.

Blanching
To blanche food you need:
A big pot to boil the water in. Wider is better so the food will have room to float around and not touch other food. Lots of water means that the boil will recover the boil faster.
A large bowl, filled with a 1:1 ration of water and ice. After about 5 minutes you will have water at 32°F (0°C). This will shock the food, cooling it down quickly and stopping the cooking process. If we just let it sit on the counter it will continue cooking until it reach equilibrium.
A spider or slotted spoon. To get food in and out of the boiling water.
Since you are working with lots of water a few towels would be handy.

For a veggie tray, you'll want to cut the foods into bite-sized pieces before blanching. Lower a spider full into the water and allow to cook for 30 seconds, then using the spider again remove them into the ice-water bath for the shock. after 1 minute they will have stopped cooking. You can dry them in a salad spinner or on some towels. If you are not going to eat them within the hour store them in the refrigerator to keep them out of the Danger Zone, wrapped in some moist towels to keep them from drying out.

Fresh Tomato Sauce
If you have a garden with tomatoes one of the great things to make is your own tomato sauce. To make a good homemade tomato sauce you should start with a tomato concassé, because the seeds are tough and bitter and the skin will curl up into nasty little tubes that never soften. 

Ingredients
20 Roma Tomatoes, concasséd

1/4 cup olive oil
1/2 teaspoon kosher salt
1 teaspoon pepper
1 cup finely diced onion
2 teaspoon minced garlic
1 tablespoon finally chopped fresh oregano leaves
1 tablespoon finally chopped fresh thyme leaves

The juice of 1 lemon

Tomato Concassé
For skinning fruit, you'll need to cut a small X in the base (non-stem end) of the fruit and lower 2-3 of them into the water with the spider for 30 seconds. Then remove them with the spider and shock them in the ice-water bath. After a minute you can peel them by rubbing them in a towel to remove the skin or if the skin is still hanging on too tight with a paring knife by grabbing the loose skin at the X we made between the knife and thumb and pulling. We live at high-altitude so we need to go for 60 seconds to loosen the skins enough. Discard skins. 

Cut the tomatoes in half and using your finger remove the seeds and pulp, discard the seeds and pulp. Chop the tomatoes into large cubes discarding the hard stem. 

In a large non-reactive pot cook on low the tomato concassé, oil, salt, pepper, onion, garlic, and herbs for about half an hour until most of the liquid has cooked out.
Add the lemon juice. Let that return to a boil. Check the seasoning and adjust salt and pepper to taste.