An impregnator for mixing a nonaerated or only slightly aerated liquid (F) with gas (G), in particular for mixing a noneffervescent or only slightly effervescent beer precursor product, or a beer precursor product containing CO2, with CO2, includes a mixing cell, in particular tubular, which except for an incoming liquid inlet, an incoming gas inlet, and an outlet, is partitioned off from the surrounding, and at least one Impregnator body is disposed in the mixing cell in such a way that the flow through the mixing cell of the liquid (F) and gas (G) must necessarily take place through the impregnator body. Disposed in the mixing cell is at least one impregnator body, which includes a porous solid body, namely of a foam material, a sponge, a follow fiber module, or a sintered material.