I have made several Victoria sponge cakes at various times only this time the sponges have sunk slightly in the middle although not easy to see in the photo. I've used the same recipe as at other times. Any ideas why this happened?
When the center sinks, that is an indication of weak structure.
If you have baked this recipe in the past with success, then the weak structure is most likely caused by mixing.
1) Wrong temperature of butter: recipes frequently, state temperature of eggs at room temperature. This is incorrect. Butter should be 65°F (18°C). if you want to read the science behind it, see the article below. Butter that is too warm will lose plasticity. When the protein denaturalization and starch gelatinization in the batter is triggered, the butter cannot hold the air bubbles long enough for batter to expand and set.
2) Over-creaming: beating the butter and sugar too long. overheating the butter, when the butter is too warm, it loses its plasticity. See above.
Other causes of cake to collapse in the center
Too much sugar: sugar to flour and/or egg in the formula.
Flour and egg are strengthener. Sugar is a weakener. When the ratio of sugar is too high, it will weaken the Structure of the cake, causing the center to fall as it cools.
Oven temperature too low and/or wrong type of cake pan:
Stages of Baking:
1. Fats melt: 92°F butter melts Butter is an emulsion of fat and water; butter separates at this temperature.
2. Gases expand and form: the water heats, then turns to steam. The steam expands the batter.
3. Sugars dissolves
4. Protein denaturation begins
5. Starch gelatinization begins
6. Gasses evaporate
7. Maillard occurs
A cake can be baked completely, but the quality of that cake will vary depending of the oven temperature and the pan as they effect when these chemical reactions of baking happen.
This blog shows cakes baked at different temperatures. You can see the difference in cake quality.
If your oven accurate? A side-by-side comparison of different baking temperatures, highlighting why accurate oven temps actually matter!
thecakeblog.com
Does your cookie recipe call for creaming the butter by beating it with sugar? Just how important is that step, and how do you know if you're doing it right? We break down the science of creaming and explain exactly how to do it.
www.seriouseats.com