apricot water [abrikosovaya]
This is really seltzer flavored with apricot, quite possibly artificially. In the summer in Russia kiosks regularly dispensed beer, kvas, or flavored seltzers. Apricot water was still marketed in Russia into the 90s, as the label below shows.
And the fact that there was no beer is also typical of Soviet life, where anything could become scarce. Woland's line in Chapter 3 that "Whatever comes up you say doesn't exist" always got a big laugh from Russians. Here is a Kvas kiosk (kvas is a slightly fermented beverage made from black bread):
The sign says "there is no kvas."