This is a thoroughly investigated space. However, recommended cooking temperatures vary widely online. I’ve tried many recipes and gotten a wide range of results. Furthermore, there may be room for more twists. To help sort things out, and in case there is actually room for more twists, here’s my version.
- Handful brussels sprouts
- Cooking spray
- Dried thyme (or some other seasoning)
- Preheat oven to 215 degrees F.
- Separate brussels sprouts into leaves. Lightly coat leaves with cooking spray. Lay leaves in single layer on baking sheet and bake in oven until crispy.
- While leaves bake, season salt by grinding salt and dried thyme using a coffee grinder or mortar and pestle.
- When leaves are crispy, remove them to a bowl, lightly spray with oil, and toss with the ground, seasoned salt.
The chips taste just fine with plain salt. However, I would grind the salt whether it’s seasoned or not. I find that grinding improves adhesion of seasoning to chip.
The first reason I recommend grinding a seasoning with the salt is depth of flavor. The brussels sprout entry in Andrew Dornenberg and Karen Page’s Culinary Artistry suggests a number of potential seasonings (see p. 98): almonds, bacon, garlic, nutmeg, parsley, rosemary, thyme, and walnuts. I seasoned with thyme salt — hence the post title — last night and Dornenberg and Page’s suggestion helped. The combination of dried thyme and brussels sprout chip worked. Note that the moister ingredients on the list above may benefit from dehydration in the oven, but I haven’t tested anything beyond dried thyme.
The second reason is that the costs of messing up are low (a little time and a handful of brussels sprout) and the benefits from successful experiments are high (new reliable snack for entertaining, learning about new flavor combinations).
Why another recipe?
The main reason I decided to add yet another of these green vegetable chip recipes to the blogosphere is that there is wide variation in cooking temperatures in recipes posted on the Web. I’ve tried several of these with inconsistent results. It seemed worth adding a discussion of the issues.
The main task in cooking a kale or brussels sprout chip is dehydrating the leaf. So the first criteria for the cooking temperature is that the oven can draw out the water. Any temperature greater than or equal to 200 degrees F (at least in my oven) qualifies.
The upper limit is determined by the relationship between heat and Maillard (i.e. browning) reactions. I prefer my kale and brussels sprout chips to brown as little as possible. I don’t like the taste, at least when these vegetables are in chip form. Maillard reactions occur at temperatures at or above 300 degrees F, so 300 degrees F is the upper limit.
So why I did settle on 215 degrees F? The main reason is oven temperature variability. An oven set at 300 degrees F will sometimes be below that temperature and sometimes be above that temperature. The lower the setting, the more likely it is that the oven temperature will not exceed 300 degrees F and induce Maillard reactions. Since I work at home, I don’t mind waiting for something to finish while it cooks at a very low temperature. I chose 215 degrees F because I wanted to be as close to (from above) the boiling point of water. Given oven temperature variability I wouldn’t be surprised if 200 degrees F worked just as well.
The other reason I settled on such a low temperature is that the window for taking something out and it being not overcooked increases as the cooking temperature decreases. In other words, there is a trade-off between cooking temperature and margin for error. Others may prefer a higher cooking temperature and at the cost of more frequent checks on the oven.