We wondered if we could use our rotary evaporator as a freeze dryer. We have an old freeze mobile which is bulky. When we obtained it years ago we bought a few new VirTis freeze drying flasks. The freeze dryer is bulky and not super efficient. We were on the verge of getting rid of it. Then while talking with Joe at Polyscience I noticed that the VirTis flasks would connect to the rotary evaporator. Unfortunately we had 2000-ml flasks which are too long. So I did what any impulsive idea chasing guy would do. I ordered 1200-ml flasks and waited impatiently. When the flasks arrived I ran to Charcoal BYOB to borrow some liquid nitrogen. I raced back home, cleaned some strawberries and froze them solid. I then put them in the flask and fired up the machine. It turns out my flask was not up for being rotated at 190 rpms. Water went flying and the container kicked itself free. I slowed the machine down and watched. My attempt at freeze drying turned out to be a complete failure. And we could not be happier. We ended up with something totally unexpected. The strawberries froze and thawed as in our cryo-blanching technique. The rotary evaporator pulled off excess moisture. and the strawberries concentrated. They became dry, sticky, and vibrant. There was no caramelization or cooked flavors. This jam is all stRAWberry.
May 6, 2010