## Thursday, January 27, 2011

### Math for Cooking, Part IV

This week's math blog has centered on the math used in recipes. So far the versions I've offered were inadequate. Both the short one (no units) and the symbol version (few words) were unusable, in my opinion. This was not an accident, but to prove a point.

Let's try an enhanced version, including all the math I can think of. In this example I have added conversions to metric units, specified how many people we can feed, how long it will take to prepare, the tools required to do the cooking, an illustration, etc.

Rice and sweet potato, with coconut and cranberries
• serves 3-4 adults as a side dish or 2 adults as a main dish
• active effort 15 minutes; total preparation time 60 minutes

INGREDIENTS
1 cup (300 g) roasted and skinned (or canned) sweet potato, mashed
1 cup (180 g) Basmati rice
2 cups (500 g) boiling water
1 tbsp (15 g) olive oil or butter
4 oz (100 g) dried sweetened coconut
4 oz (100 g) cranberries (frozen, fresh or dried)
1 tsp (6 g) sea salt
1 tsp (6 g) black pepper

TOOLS
Large (12-inch) skillet with oven-safe lid
Spatula or spoon for stirring rice in skillet
Pot or kettle to boil 2 cups of water
Oven large enough for skillet
Measuring cup and spoons or food scale

METHOD
1. Heat the oven to 275°F or 140°C  [Gas Mark 1 if you are in the UK]
2. Put the skillet on a large burner.
3. Set burner to medium-low heat. Let the pan heat for 2-3 minutes.
4. Using a pot or tea kettle, start heating 2 cups of water to a boil.
5. When the skillet is hot, add the olive oil or butter and give it a moment to heat.
6. When the oil is hot, stir in the Basmati rice.
7. Stir the rice for 5 minutes, or until a few grains begin to turn a toasty brown color.
8. Add sweet potato to the pan.
9. Stir the mixture to integrate the rice and sweet potatoes.
10. While continuing to stir, slowly pour the 2 cups of boiling water into the skillet.
11. Add the coconut, cranberries, salt and pepper.
12. Turn off the burners for skillet and boiling water.
13. Put the lid on the skillet. Put the covered skillet in the oven.
14. Leave in oven for 40 minutes. Do not open lid during this time!
15. Carefully take hot skillet from the oven using hot pads, and remove lid. Turn off oven.
16. Fluff and mix the rice with a fork, and allow to cool slightly before serving.
Was that too much? Did I need to tell you to turn off the stove-top burners and the oven? Remind you to turn on the lights in the kitchen if it was dark outside? Specify that you buy ingredients at your local market? Recommend favorite brands? Insist on Ocean Spray™ cranberries? Warn that I meant the actual fruit and not the Irish rock band?
Where do we stop? While developing this blog my sister sent me a recipe for fried mackerel. After the author finished describing the cooking method, he added a postscript,

"I forgot to tell you to open the windows to reduce the fishy smell ... although I suppose you worked that out for yourself."

In any writing endeavor, you have to decide how much to say, and how much to leave the readers to work out on their own.That applies to recipes, and to math problems.