3,383. The Bracha on Separating Tithes

Hilchos Maaser 1:15

If someone takes just some of the maaser, it’s not maaser at all. Rather, it’s as if someone just divided their pile of grain. One must, however, take appropriate maaser from the part he put aside, as follows: Let’s say that someone had 100 seah as produce and he put five seah aside as maaser (rather than the ten seah required). These five seah aren’t maaser, but one can’t take maaser for them from elsewhere. Rather, one must take half a seah from them as their maaser.

Hilchos Maaser 1:16

When taking maaser, one recites a bracha, the same as one does before performing any mitzvah. Similarly, one recites a bracha before taking maaser sheini (second tithe), maaser ani (the tithe for the needy) and terumas maaser. One recites a bracha on each of these individually. If one separated all the tithes one after another without speaking in between them, then he should recite one bracha over all of them, specifically that God “commanded us to separate terumos and maaseros.”