Thursday, July 14, 2011

Sorbet Series: Sour Green Apple



After our successful results with melon, Rachel and I flung open the fridge and pondered which ingredients we could sorbetize this week (dear Blogger spellcheck: sorbetize is obviously a real word; please stop putting rude red lines underneath it).

Although Israel's formal period of austerity may be decades behind us, a glance inside our fridge during a typical weekday suggests that this young couple is bringing it back in style. Our produce stash consisted of some tomatoes and cucumbers, a bit of spinach, and apples. Apples it is!

We had a combination of tart Granny Smiths as well as those sweet green apples they only have in Israel, and are otherwise known as the Best Apples Ever (unless you are Rachel and prefer Granny Smiths). This was not a problem; in fact, blending tart and sweet proved to be the defining characteristic of this sorbet.

We also had half a bottle of sweet dessert wine brought to us by a guest last week, which was perfect. Not only would the sweet white wine complement the apples, but the alcohol would help by a) keeping ice crystal growth in check, thus giving us a smoother product and b) making our sorbet alcoholic.

As I'm sure you remember from the last sorbet post, we don't have an ice cream maker and so our technique consists of freezing chunks of fruit, then blending them in the food processor along with simple syrup. Thus we were faced with our first challenge, for apple chunks tend to brown pretty fast. The solution is science. I will spare you the lecture on polyphenol oxidation pathways, though, and just say that you can keep sliced apple from turning brown by using something acidic like lemon juice. Common household knowledge.

But why use lemon juice when you have... citric acid? Citric acid is a popular pantry item in Israel, mostly because it's very effective at removing the white chalky calcium deposits that foul up one's קומקום thanks to Israel's very hard water. Why? Because it's an acid! Haven't you been paying attention?

Citric acid has another use, however, and that is giving sour taste to things like sour candies. We don't do a lot of candy making, but it struck me that by coating our apple chunks in a citric acid solution, we could both keep them from browning and make them nicely sour. I didn't measure, but I'd estimate I used maybe a teaspoon of citric acid in a 1/4 cup of water. You can sort of just mix the solution until its sour enough, but not too sour. Then we put it in a ziplock back and Rachel tossed in the apple pieces as she cut them. And then we froze it.

There was a second challenge. Most online recipes seem to indicate that simply freezing apples and blending them would make a less-than-smooth sorbet. They generally recommended cooking the apple first. This is because cooking helps release pectin from the apple, and pectin makes the sorbet smoother. But this also makes the sorbet brown.

Instead, we turned to an ingredient that is relatively obscure, but most definitely a rising star in the culinary world. I give you: xanthan gum. Xanthan gum has been used in the food industry for ages, but only recently has it started appearing on more mainstream shelves. Why? Because it's indispensable for people doing gluten-free baking, and that market has been definitely growing lately.

But that only explains why it's easier to get. What does it do? Again, I'll spare you the lecture and boil it down to this: everything. If you have a texture issue, xanthan gum will solve it 9 times out of 10. I know I'm being a little silly and unscientific, but trust me when I say that one container of xanthan gum in your pantry will a) allow you to change the way you make tens, if not hundreds of dishes and b) last you forever, since you usually only need to add it in fractions of a teaspoon.

Also - I know xanthan gum starts with an "x", but don't be afraid. It's made from plant stuff. I would even call it "natural", but the distinction between natural and synthetic when it comes to food is kind of a pet peeve, and I'd rather not get into it. The bottom line is that xanthan gum is safe, and expect to see and hear about it more in the future. You heard it here first.

Fortunately for us, there's a natural food store just a short walk from the Technion gate, and they carry xanthan gum. A container set us back some 40 shek, but, like I said before, this stuff lasts a long time.

With all the necessary ingredients, we got to work. The apple chunks were easier to grind, but they needed more liquid to come together than did the melon, so it's a good thing we had wine in addition to our syrup. And the xanthan gum was key. Before it, our sorbet was good but slushy. With it, it became smoother, like icy applesauce. We started with 7 apples, which took 3 shifts in the food processor. Each time I added about 1/4 of a teaspoon of xanthan gum. For a final touch, I shook in a little more citric acid to give the sorbet a tart kick in the pants.

The result? I think this sorbet is phenomenal, and our best (of two, ok) yet. Rachel preferred the melon, mostly because she likes melon better than apple.

Anyway, time for me to get back to studying for my last final. Among other things, it covers xanthan gum!


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