In the process of making powdered liqueurs for future use, I've been trying to figure out the best method to get liquids into solids. I'll be comparing the microwave to the oven to the food dehydrator, using Campari as my first liqueur in all of them.
In today's post we'll look at using the oven. Following the suggestion of Don Lee on this eGullet thread, I purchased silicone cupcake cups to experiment with. They can be used in the microwave or oven and are easy to clean.
In all of my oven experiments, the procedure was the same. I filled the cupcake cup with 2 ounces of Campari, put it on a cookie sheet, and put it in the oven. Most of the time I cooked the liquid for 12-24 hours.
Dehydrating Campari at 140F and 170F (in separate trials), the liqueur would dehydrate and get clumpy. I'd then squeeze the cupcake cup a bit to break up the clumps and expose any wet spots so that it would dry completely. In the end I had a combination of powder and pebble-sized clumps of dehydrated Campari.
At 200F I had clearly reach some sort of candying state with the sugar. It looked like it was still watery with liquid, but on further inspection it was closer to a melted lollipop- very brilliant liquid sugar. On removal from the oven it formed a hard puck shaped like a Reese's Peanut Butter Cup.
At 250F the sugar burns a bit, becoming brown in color and smelling more like molasses. It also stays liquid and forms a hard puck in the bottom of the cupcake cup.
On tasting after grinding these with a mortar and pestle, I found that the 250F Campari tasted like brown sugar or molasses with a bitter Campari twinge to it. It wasn't nearly as bad as I expected but I am not sure how I'd use it. Campari gingerbread cookies, perhaps?
The 200F powdered Campari had a distinctly sharp bitterness to it. The 170F Campari powder had the best and most Campari-esque flavor of all, with that great Campari brightness still present and a balance of sweetness from sugar with the heavy bitterness there too. The 140F powder was also very good, but I prefer the 170 at least on this first experiment.
Another reason to use the lower-temperature Campari powder is that the others were harder to crush up (like crushing a lollipop instead of granola). They also seem to want to stick together. After crushing, they get clumpy. (I tried reheating at a lower temperature to see if it would stop clumping, but it just formed back into a blog and I had to re-crush it again!) Clumpy clusters are probably be fine for baking purposes, but not practical for rimming cocktail glasses.
Long story short: Oven at 170F worked best for me.
In the next post, we'll look at using the microwave to dehydrate liqueur.