Saturday, November 17, 2007

Apple-quince galette, version 2.0

photo of an apple-quince galetteI tried the apple-quince tart again last weekend, using what I learned from the previous attempt. This time I sliced quince and apples thinner and was much more careful about how I placed the fruit on the tart -- instead of arranging the apples and then haphazardly dropping the quince on top, I alternated apple, apple, quince to evenly disperse the pieces.

The result was a lot more beautiful, as the picture above illustrates. A few flaws, like the piece of pie shape (I am not very good at rolling dough into circles and cutting a circle out of the dough would have let to a lot scrap), and failure of the quince to turn the deep red that I was hoping for.

As before, the crust was wonderful. The thinner apples cooked more thoroughly and make a wonderful pairing with poached quince.

You can find the recipe for the apple galette in the New York Times archive. David Lebovitz has instructions on poaching quince.

Quince Caramel and Bénard Cells
The sugar syrup in which I cooked the quince went to good use in Pim's quince caramels. Oddly, Pim's recipe calls for salted butter, which leaves a far amount of uncertainty in the salt content. If that bothers you, here are the proportions I used:

1 1/4 cups quince-infused syrup (follow Pim's directions to make this)
3 oz. unsalted butter
1/4 t. salt
1/4 t. fleur de sel

To make the caramels, follow Pim's instructions. Add the salt after the final mixture reaches the target temperature, turn off the heat as directed, and carefully stir to incorporate the salt (the caramel is very, very hot). I added the salt at the end to prevent the fleur de sel grains from dissolving.

The picture below is the quince-infused syrup just before it started boiling.

photo of quince sugar syrup
The process of making the caramel revealed some subtle beauty in heated sugar syrups. As the syrup heated, bright lines formed in the syrup. I'm guessing that fluid circulation is the cause and that I was seeing something like Bénard Cells. Here's what is probably happening: the liquid at the bottom of the pan is receiving the most heat from the burner. As its temperature rises, the fluid becomes less dense, causing it to rise. But you can't have all of the fluid rising -- some of it needs to be sinking to replace the rising fluid (unless you have a stable inversion, something that is not likely in a saucepan). The bright lines are the result of the gradients in temperature, density and refractive index between the rising and falling fluids. The varying refractive index across the cells appears as lines, or Schlieren.

The patterns are quite captivating (to me anyway), but hard to photograph without additional equipment like a fan or lens purge device to keep water vapor from condensing on the camera lens. Perhaps next time I make the caramels (or another quince-syrup inspired confection, like quince-caramel sauce, or some kind of pudding) I can rig up something to capture the beauty in the syrup.

Random link from the archive: Smoked Eggplant

Technorati tags: Baking : vegetarian : Food

Wednesday, November 07, 2007

Slow-roasting tomatoes in a solar oven

In the last few weeks I have been making many batches of slow-roasted tomatoes. These are tomatoes -- typically Roma, San Marzano, or another sauce-friendly tomato -- that have been sliced, tossed with olive oil, salt and pepper, and then roasted on a cookie sheet at 250 to 300 F for several hours. The slow cooking concentrates the flavors, creating a supercharged tomato experience. Consequently, the roasted tomatoes are best used as accents, as a topping for free-form lasagna, in macaroni and cheese, or as part of a sandwich. The ones I don't eat I put into the freezer.

But it takes a lot of fossil energy to slow roast tomatoes, and so I have been trying to use my solar oven.

Drying fruits and vegetables in a box-type solar cooker like mine is tricky because the oven works best when the cooking chamber is sealed. Drying something, however, requires a constant flow of dry air; otherwise, you're creating tropical rain forest-like conditions, where nothing ever dries out. There are special solar dryers that address this problem, which I might look into next spring. But in the meantime, adding a few kitchen items to my oven made my drying project a reasonable success.

The diagram below shows how I did it. The Roma tomatoes (sliced in half and heavily salted to draw out the moisture) are placed on a wire rack, which goes on a cookie sheet, which goes on an upside-down bowl. This stacking gets the tomatoes close to the glass, and increases the level of solar energy. To allow air exchange, I placed rolled up towels under two corners of the lid. This created a path for air to enter and exit the box without losing too much heat.

Since it was October, the day was fairly short and the sun was low in the sky, so the result of this experiment was half-roasted tomatoes. Fortunately, I was baking pizza that night, so I put the tray of tomatoes into the oven after I turned it off -- the heat retained by the oven and the baking stones was enough to finish the roasting.

Next summer, I think I'll start my solar drying experiments in June...

Random link from the archive: Smoked Eggplant

Technorati tags: Food