Biscotti

Today we tackled biscotti, an Italian cookie that is baked twice. The class collectively followed two nearly identical recipes; the only difference was whether we used olive oil, as in southern Italy, or butter, as in the north, as the fat. For our biscotti, we used olive oil.

First, we toasted almonds until they were browned, then chopped them finely.

Almonds fresh out of the oven and looking…brown?

While the almonds toasted, we combined eggs, lemon zest, sugar, olive oil, almond extract and vanilla and whisked them together. In another bowl, we mixed flour, baking powder, salt, and the almonds, once they were finished. We then added the dry ingredients to the wet and stirred until the dough became stiff.

All the ingredients combined

We then formed the dough into a rectangular log and baked it for about half an hour.

The dough in the oven

We then cut the log into biscotti and baked again at a lower temperature for seven minutes.

Sliced and ready to be baked again

The finished biscotti

1. Why is butter a solid at room temperature while olive oil is a liquid?
   Fat’s melting point, and therefore its state at room temperature, is dictated by the shape of the triglycerides that make it up. Saturated fats are straight, so they can stack closely, allowing for lots of Van Der Waals attractions. Unsaturated fats are bent, and do not stack as well, so there are fewer VDW attractions between them. In order for something to form a solid, its molecules must stabilize, which occurs through VDW attractions in fats. Therefore, the more saturated fat something has, as compared to unsaturated, the higher its melting point will be. Butter is about 50% saturated fat and 50% unsaturated, while olive oil is only 15% saturated and 85% unsaturated, so butter would have a higher melting point.
2. Explain the textures of the two different types of biscotti based on the effects of water content.
   Foods with high water activity are more moist and chewy, and foods with lower water activity are more dry and crunchy. Butter is 15% water, while olive oil is pretty much 100% fat, and <1% water. Therefore, biscotti made with butter has more water in it than biscotti made with oil.
3. What effect does the fat/oil have on gluten formation in the dough? What about your biscotti supports your conclusion?
   Fat inhibits gluten formation by coating the flour and limiting amount of water that reaches the flour. This is evident in the biscotti because it is crumbly and dense, without large pockets of air.

Both kinds of biscotti