Where is it written that hamburgers must be round?
I had learned how to use the Vacuum Former at TechShop San Jose, and needed a project to make sure I remembered how to use it. Also, I wanted to test the theory that a hole in the center of a burger will help it cook more quickly and/or evenly.
Herewith, the delicious results of my experiment.
Step 1: Cut the Positives Out on the CNC Wood Router
To make the positive for my mold, I used the ShopBot at Techshop. I still had a "gear" file from class, and made several 4" gears, some with holes in the center, others solid. I had guessed that a 4" gear would yield a four ounce burger, i.e. a quarter pound, and they came out pretty close.
Step 2: Vacuum Form the Molds
I placed the positives in the vacuum former, secured the PET-G food-safe plastic, heated it and vacu-formed the molds. The hardest part was extracting the gears from the plastic, as the sides were perfectly vertical. Normally one adds a bit of a "draft angle" to the positives, so that they are larger at the base than at the top to ease extraction. Since I was not in a hurry, nor was I doing a production run of the molds I just dealt with the annoyance.
After a few minutes of flexing and pushing, I had molds for my gear-shaped burgers.
Step 3: Molding the Burgers
Back home, I mixed up a batch of burger meat. I used 15% fat hamburger, and added some salt, pepper, garlic seasoning and some italian bread crumbs to add a little structure to the mix.
First, I sprayed a little non-stick spray into the mold. Next, I smushed the meat into the mold, flipped it over and flexed it until the burger popped out.
I made a couple each of the hole and non-hole burgers.
Step 4: Grill 'em and Eat Them!
Off to the barbecue.
I grilled a couple and flipped them at the same time. Once done, I cut them open to check done-ness. The ones with a hole in the center were more done, but there was not as much difference as I had expected. Both styles were delicious.
One surprise was that the patty with a hole in it was more recognizable as a gear after cooking.