sourdough
part of speech
noun (sourdough, uncountable; a sourdough, sourdoughs for loaves)
meaning for a pupil
1) Sourdough is bread made with a starter, a mix of flour and water full of wild yeast and bacteria, instead of packet yeast; it tastes slightly sour. tree →
2) A sourdough starter is the bubbly mixture kept alive and «fed» with flour and water to make this bread. tree →
3) (US, old) A sourdough was an old-timer in Alaska or the Yukon, especially a gold prospector. tree →
sense in the lessons
In science lessons it shows microbes at work: the yeast makes carbon dioxide gas, which makes bread rise, and the bacteria make acid, which gives the sour taste. In everyday life many families bake sourdough at home. Phrases: «a sourdough loaf», «sourdough starter», «feed the starter».
examples
- We had sourdough toast for breakfast. tree →
- Our sourdough starter bubbles because of the wild yeast. tree →
- Feed the starter with flour and water every day. tree →
- Sourdough tastes a bit sour because of the bacteria. tree →
- The bakery sells a crusty sourdough loaf. tree →
- Gas bubbles from the yeast make holes in sourdough. tree →
- San Francisco is famous for its sourdough. tree →
note
Uncountable as bread (some sourdough), countable as loaves (two sourdoughs). It is one word. The sour taste is from lactic acid, the same acid as in yogurt.
Trees and pragmatics
Every meaning and example of «sourdough» parsed by Mova, each sentence with its dependency tree and frames.