It's gotten mechanical leavening from a tonne of butter that is sitting in pockets there.

它是用许多黄油进行机械发酵，然后放到容器里烤。

Brownie isn't something that's meant to be fluffy so it doesn't have a ton of leavening in it.

布朗尼不是那种蓬松的东西，所以里面没有大量的发酵剂。

Back before grocery stores and fancy cake recipes, if you wanted to make your bread rise, you needed leavening agents from natural sources.

回到杂货店和精美蛋糕食谱之前，如果你想让你的面包发起来， 你需要天然来源的发酵剂。

So bakers started using chemical leavening agents like baking soda, which, if we were to use the actual chemical name, we would just call it sodium bicarbonate.

因此，面包师开始使用小苏打等化学发酵剂，如果我们要使用实际的化学名称， 我们会称之为碳酸氢钠。