3,444. Designating Maaser Ani From Demai

Hilchos Maaser 9:3

Even if one doesn’t take the tithe for the needy from demai, he still must designate it. He declares one-tenth of the produce to be tithe for the needy. This is a necessary prerequisite to obligating the produce in second tithe (which the owner must take). The tithe for the needy is taken in the third and sixth years of the shemittah (sabbatical) cycle, while second tithe is taken in other years.

Hilchos Maaser 9:4

No bracha is recited when taking terumas maaser and second tithe from demai because this is only done due to a doubt. Therefore, one may separate such portions while undressed.