Kiddush – How Much Wine

The Aish Rabbi Replies

There is no maximum size for a Kiddush cup. The minimum size is clearly stated. A Kiddush cup must hold what’s known as a revi'it (literally, “a quarter”) – 1/4 of a “log” (Shulchan Aruch 472:9). How big is a revi'it? The Talmud (Pesachim 109a) measures it in terms of thumb widths – as the equivalent of a cube of dimensions 2x2x2.7 “fingers.” Elsewhere a log is defined as the volume of 6 eggs, making a revi'it 1.5 eggs.

Needless to say, there is much discussion in the more recent commentators exactly what these measurements mean in modern units. They note in particular that the two measures hardly square: Either our thumbs are somewhat larger than they were in Talmudic times or our eggs are smaller. (The former is actually much more likely.) As a result, opinions vary drastically – anywhere from under 3 ounces to over 5.

What should one do practically? There is another relevant distinction. On Friday night there is a Torah obligation to recite Kiddush, based on the verse “Remember the Sabbath day to sanctify it” (Exodus 20:8). By contrast, the Kiddush of Shabbat day is a rabbinical obligation – as a way of lending importance to the meal.

Thus, for the Friday night Torah obligation, one should be more meticulous and use a larger measure, based on the thumb measurements. A common practice is to follow the measurements made by one of the great rabbis of 20th century America, Rabbi Moshe Feinstein, who measured a revi'it as 4.42 ounces (130.7 ml). Others are more stringent to follow one of the past leading Israeli rabbis, the Chazon Ish, and to drink 150 ml = 5.07 oz.

On Shabbat day smaller measurements based on the volume of eggs is sufficient. The most accepted opinion for this (R. Chaim Noeh) is 86 ml, which is a bit over 2.9 oz.

Now how much of the cup should you drink? That is actually a separate question which I dealt with recently. Please see here for the response.

I should also mention that the cup should be filled completely even if it holds much more than the prescribed amount and more than you intend to drink (Rema 183:2).