Using alcohol in Croissant Dough

I've tried 2 methods for infusing rum into the dough. The first was substituting 25% of the water for 70 proof rum. Which resulted in a firm dough with a lighter flakier cronut with a subtle rum flavor. While it was flaky, it was not to that of a normal croissant. It was a mix between a doughy pastry and a croissant. I didn't find too much of a problem with the gluten not activating as I did give both doughs a little extra time resting.

The second, I reduced 120 proof rum and whipped it into butter. The result was a stickier, softer dough with a stronger rum flavor but the cronut was more like a doughnut. The dough was heavy and not flaky at all. I think the rum reduction reduced the integrity of the butter which is why it was more doughy.

Overall the substitution for 25% of the water was the winner on flavor and texture. Also as it was my first time making croissant dough, I feel like I could improve my technique to get a flakier rum cronut or croissant.

Agreed with Peter Gordon. The other reason why vodka works in pie crust is because the high proof means it will evaporate quickly, so it helps to bind the ingredients without making it overly soggy. So if you substitute water for alcohol you will also mess with the amount of wet ingredient needed for the dough. I'd suggest you not substitute the water but instead, heat some rum to make a reduction (thus lowering alcohol content), then beat into your butter for a rum flavoured butter. That should give you rum flavour without compromising the integrity of the dough, and the fact that you're concentrating the rum should give you a strong rum aroma.

Maybe try brushing the dough with rum before folding/rolling it out? That would give you the flavor without messing with your gluten.

I think I would try using rum as part of a filling rather than putting it into the dough. Unless you are up for experimentation, croissants are enough work that you don't want a failure on your hands. Perhaps a filling of raisins, chopped nuts and rum would add the flavor without mucking about with the dough's consistency.

What an interesting question. I've ruminated over it for a couple of hours. 80 proof rum is actually about 2/3 water, so it will clearly activate some gluten. The flip side is that alcohol is one of 7 things which will denature, or change the initial nature of, any protein. So the alcohol in rum will to some extent weaken the gluten, or protein, structure of your dough. The question I come to is how to compensate for that, or even if you need to. Laminated doughs require decent gluten development because protein strands (long, complex, sinuous molecules) are quite literally shortened, that is to say, broken and interrupted by fat. In the case of croissants, that's butter and lots of it. You could certainly boost the protein content of your bread flour by adding vital wheat gluten. But before you try that, I would suggest that you go ahead and try out your idea. Start with replacing, say, 25% of the water with rum. It will tenderize your croissants, and to what extent will be the interesting answer. Please keep us posted. This is a very interesting project, and I'd love to know how it turns out.

The function of water in the Croissant is to develop the gluten in the flour. Thin layers of dough require well developed gluten. Rum flavoring could work but the alcohol in the extract or straight rum will not develop gluten. One of the tricks in making pie dough is to use vodka because there you don't want gluten to develop as it makes the crust "chewy".