Kitchen Mysteries is a weekly exploration of oddities surrounding cooking and food. They could be recipes that fail when they shouldn't, conflicting advice from different sources, or just plain weirdness. If it happens in a kitchen, and you're not sure why, send a tweet to The Food Geek to find out what's happening.
megmaker asks via twitter:
When one thinks about the differences between different flours, the first thing that leaps to mind is its protein content, and consequently how much gluten it can make. It occurs to me that I haven't really had a chance to discuss gluten here at Fine Cooking, and I love discussing gluten. Yes, it is sometimes far too exciting to be with me at a cocktail party, I find no time to be a bad time to talk about gluten.
Wheat, and the flour that we make from it, is the unique source of a pair of proteins called glutenin and gliadin. If you mix these two proteins together with some water, they will join together to form very long strands of gluten. Gluten provides the structure and strength to our wheat-flour based products, and is the reason why wheat is so popular of a grain. Harold McGee tells us in On Food and Cooking that the Chinese call gluten "the muscle of flour," which is a really great way of thinking of it.
Gluten let's you do two things: stretch your dough and shape it. Glutenin gives gluten its stretchy ability, or elasticity. Gliadin gives gluten its ability to hold a shape, or plasticity. Depending on how you've been working your dough, one or the other will be more active. If you've been kneading a bread dough, for example, the glutenin will be very active, and thus any stretching you do will snap right back into place. Once you let the dough rest for 20 minutes or so, the glutenin relaxes, and thus the gliadin will allow you to shape the dough and keep it that way.
There is a balance to consider, though, when you want a specific texture. Gluten imparts a certain amount of toughness to the cooked food, which is why with muffins you want to limit the amount of mixing you do, and why with cakes you want to use a low-protein flour. It's also why vodka makes for a good addition to a frying batter: relatively little of the liquid volume is water, so you can make everything into a wet batter with not that much gluten being formed.
There was even a competitor on Iron Chef, the Japanese version, that used liquid nitrogen when he was making his pasta, to control the texture. He never said why, but the best I can figure is that the low temperature prohibited gluten formation, so he was probably able to incorporate the ingredients fully with minimal gluten formation.
Still, nothing is ever quite as simple as just "gluten content." After all, semolina is a wheat flour, made from durum wheat, one of the protein-heavy wheats used in many pastas. However, it's a coarser grain, which means that it's not going to produce as much gluten as a finely-grained durum flour with the same amount of work. It is a tough little granule, though, so it makes working with the dough more of a chore, and it will give a heartier texture to the pasta when it's cooked.
Your question, though, was, "which would make a better handmade pasta, semolina or traditional wheat?" To which I say, "What do you like?" Fresh pasta is not inherently better than dried pasta, it just has a different texture and flavor. Each is great for different things. If you don't mind the extra work with semolina, and you like the texture of yours, then semolina is clearly superior. Still, it wouldn't take much to make a batch with a more refined flour. If you are looking for a more delicate texture, refined is the way to go. Most likely, it depends on what kind of mood you're in.