The original Lopez-Alt article merely claimed that the alcohol has a lower boiling point, and therefore all evaporates during baking.
Alton Brown's show went further, pointing out that alcohol doesn't just evaporate quickly, it also doesn't form gluten while it's around. I don't quite remember whether he also claimed that the alcohol actually inhibits the gluten-forming action of the rest of the water.
Clearly more data is needed. Or perhaps some primary-source citations, but they don't taste as good.
As for the soup phenomenon: It could well be a temperature thing, and I will put my vodka in the freezer next time and see how that goes. But it could also be a flour thing, I suppose. Every flour has a different protein content, every region has its favorite mix of flours (in the south, for example, you can actually buy the flour that makes Southern biscuits famously soft and tender), so unless we set out to use the same weight of the same flour we're going to tend to see different results. (My flour is King Arthur unbleached all-purpose, by the way. I'm not sure of the extent to which King Arthur is a national brand.)
Alton Brown's show went further, pointing out that alcohol doesn't just evaporate quickly, it also doesn't form gluten while it's around. I don't quite remember whether he also claimed that the alcohol actually inhibits the gluten-forming action of the rest of the water.
Clearly more data is needed. Or perhaps some primary-source citations, but they don't taste as good.
As for the soup phenomenon: It could well be a temperature thing, and I will put my vodka in the freezer next time and see how that goes. But it could also be a flour thing, I suppose. Every flour has a different protein content, every region has its favorite mix of flours (in the south, for example, you can actually buy the flour that makes Southern biscuits famously soft and tender), so unless we set out to use the same weight of the same flour we're going to tend to see different results. (My flour is King Arthur unbleached all-purpose, by the way. I'm not sure of the extent to which King Arthur is a national brand.)