It can be used. Increase the dosage when using it. After the shelf life, its activity is only reduced, and it will not endanger health.
However, it is not recommended to use expired yeast, which cannot make steamed buns, because the activity of expired yeast is very low.
The so-called test of yeast activity is to dissolve yeast in warm water (sometimes a little sugar can be added), which used to be one of the necessary steps in baking bread. The foam and distinctive smell produced during this process indicate that the yeast is still alive.
However, the expiration date is marked on the yeast packaging now, so we don’t have to guess whether it is active or not, but people still want to confirm this factor before baking and often test the activity of yeast. And if the yeast used in baking is compressed yeast, then the inspection step must not be omitted.
Because the storage period of compressed yeast is very short, if it is confirmed that it has not lost its activity at the beginning, then it will not be a headache to find the problem in the later stage of baking.
However, remember not to perform the above tests on instant yeast. Because this kind of yeast is designed to ferment dough quickly, the detection process will use up most of the activity of the yeast, and there will not be much activity left when it is used on the dough.
To test the activity of yeast, we need to:
- Mix one tablespoon of yeast, 1/4 cup of warm water (43°C) and 1/2 teaspoon of granulated sugar.
- Stir well and let it stand for 5 minutes to see if there are any bubbles. If there are bubbles, it means that the yeast is active.
If you decide not to test the activity of the yeast, but in the subsequent baking, it is found that the original yeast has lost its activity – the performance is that the dough is fixed in the pan, and the size has not changed. Don’t despair. At this time, we can add yeast to the dough to reverse it. situation. Of course, the yeast added here will be tested first.
When adding yeast, it may be necessary to add some flour to maintain the ratio of ingredients, then knead the dough again, cover and ferment, and it should be feasible.
