CATALYTIC REACTIONS?

If you have a photo or other graphic that reflects an aspect of life (including laboratory life) or a quotation that scientists mightappreciate that would be fit to print in the space to the right, why not

send it to us via e-mail:

<catalyst@nih.gov>; fax: 402-4303; or mail: Building 2, Room 2W23.

Also, we welcome "letters to the editor" for publication and your reactions to anything on the Catalyst pages.

In Future Issues...

On the Road(map): A Series

Intramural Database

Dipping into Poolesville

Kids' Catalyst

For the shopping cart, you’ll need: Twelve ounces (oz) of semisweet chocolate broken into four 3-oz groups. Subdivide these groups into squares, about six each. Keep them separate and don’t nibble! A half-pound of butter (two sticks), divided into four 4-tablespoon (Tbsp) groups that have been cut into pea-size chunks (about 60). Put two of the 4-Tbsp groups in the freezer; keep the others at room temperature. Three-quarters of a cup of coffee, with or without caffeine.

For hardware, you’ll need: A large coffee mug A small whisk or large fork A tablespoon measure A microwave set to half-power An oven mitt (the cup will be hot. Taste buds!

Now we’ll see how combinations make all the difference.

First Experiment: Take 3 Tbsps of coffee and put it in the coffee mug. Take one 3-oz chocolate group, and add one small square of chocolate to the coffee. Put this in the microwave on half-power for 15 seconds. Check the mixture. The chocolate should be soft enough to melt into the coffee when stirred. Now repeat with each square of chocolate. All melted? Now, take one 4-Tbsp group of cold butter and add that, one pea-sized chunk at a time. What do you get? Cool this mixture for 15 minutes, stir again, and taste! Yum!

Second Experiment: Take the second 3-oz group of chocolate and put it ALL in the coffee mug. Heat at 15-second increments (still on half-power) and stir each time until it's all melted. (This whole process should take about a minute.) Add 3 Tbsps of coffee all at once. It looks a lot different, right? Add the cold butter using the same method as the First Experiment. This looks different, too. Wonder why?

Third Experiment: Take 4 Tbsps of room-temperature butter, melt that in the microwave (about 15 seconds), then add one of the 3-oz groups of chocolate all at once. Stir until melted, then add 3 Tbsps of coffee. It tastes good, but it’s not icing!

Fourth Experiment: Take 3 Tbsps of coffee, add the last 4-Tbsp room-temperature butter group, and heat these two ingredients until the butter melts. Then add the final 3-oz group of chocolate, one square at a time, to this mixture. Wow!

You have just produced chocolate icing, paste (ganache base–look that one up), unusable glop (unless you can figure out a way to use it), and a base for very rich hot chocolate. Which is which? You can also experiment with cooling and reheating these mixtures. What you’re doing is creating—or breaking—a suspension of chocolate in relation to the liquid and the fat. . . . What would happen if you used chocolate with a higher fat content?

—Jennifer White