Often people ask me whats the proper way to reheat pasta without having it get dehydrated, there are a few acceptable methods in the pasta world, obviously microwave is not one of them, but if you have to I’ll give you a tip on that one as well.
Just like most thing in the pasta univers, it is usually about simplifying the flavors, and the same goes here, if you want your pasta not to be dehydrated the simple solution is to make sure it has enough liquid to remain saucy and moist. in many cases this means adding some of the original liquids used in the original pasta sauce while the reheating process. so for example if you are reheating your bolognese sauce, since you made the bolognese with wine and milk it makes sense that you’ll add a bit here while the heating process.
The same goes if you heat your pasta in the microwave, simply add a bit of liquid to it, or place a wet napkin on top of it.