of the Rabbinical Assembly in Israel


Bet Midrash Virtuali



One must drink from the kiddush goblet a cheekful [of wine]. That is to say, as much as could be held in one side of the mouth and one's cheeks would bulge [because of the wine they are holding]. This [amount] is most of a revi'it.


Paragraph 13 of section 271 seeks to establish the minimum amount of wine that one must drink in order to fulfill the duty of kiddush. If one takes only a sip of wine one has not fulfilled the duty. Two definitions are given of this minimal amount. The first is relative and will vary from person to person. The amount of wine that must be drunk is the equivalent of the amount that one could imbibe and then hold in one side of the mouth, an amount that would fill out the cheeks. The reason for this is so that one will have drunk "an appreciable amount" - an amount that for you, as an individual, will activate the sensation of truly having had a drink of wine.

One does not have to drink the whole contents of the kiddush goblet. If the goblet is a large one it will be brimful (as we learned in the previous shiur). But if one drinks from that goblet the amount of wine already mentioned one has fulfilled the duty.

Of course, it would be much more convenient if we were to assess this minimal amount in more exact measurements. Rabbi Karo does give an alternative measurement, one that is based on a standard measurement of capacity rather than the size of the individual's cheeks. The reason why the relative amount is given first is because in certain cases it will over-ride the measurement of a revi'it: a person whose cheeks are very large and hold much more than one revi'it cannot make do with the smaller amount, but must drink his 'cheekful'.

The standard measurement that Rabbi Karo gives is the revi'it that we have already mentioned. The Hebrew word revi'it means 'one quarter' and refers to one quarter of a certain unit of capacity used by the sages, the log. When we studied Tractate Tamid we noted:

The basic unit of cubic measurement was 'an egg's bulk' [beytzah]. It is customary to compute this as the equivalent of about 80 cubic centimetres. Twenty-four of these made up one kav, which would bring us to about 1.92 litres. Six kabim made up a se'ah (11.52 litres). Thirty of these made up one kor.

Because our main interest was at that time to explain the enormous size of the 'Ash Pile' on the main altar in the Bet Mikdash we did not bring the smaller equivalents. Six 'eggs' bulk' made up one 'log', which was therefore about 480 cc. It follows that 'one quarter' of a log would yield about 120 cc. (I must add here that there are today two main views concerning these equivalents. For various reasons, that should not detain us here, Rabbi Avraham Yeshayah Karelitz (1875-1953), the Ĥazon Ish, was of the opinion that 'their eggs were then bigger than ours today' and computed a maximalist table of amounts. Another view, for equally cogent reasons, was minimalist. According to the maximalist view 'one quarter' [revi'it] contains about 150 cc's, whereas according to the minimalist view it contains only about 90 cc's.

When we studied Tractate Berakhot we had some considerable discussion about the maximalist view of the Ĥazon Ish. If 'their eggs were bigger than ours today' perhaps we must pity the poor hens that produced them! I wrote:

Amounts of food in rabbinic parlance are measured in terms of other items: olive's bulk [ke-zayit] egg's bulk [ke-beytzah] and so forth. Modern poskim have tried to give these terms modern equivalents, but there is considerable disagreement. Let's say that a ke-zayit is something in the region of 25 to 30 cc.

One of the participants wrote the following comment:

I have heard and marveled at these modern equivalents for some time, as they seemed grossly exaggerated to me. Your shiur today prompted me to actually measure. I used the water displacement method for #1 and #2 eggs, and measured 61 and 46 cc respectively. The only olives I had on hand were Beit HaShita pitted green olives. Because they were pitted I couldn't use the displacement method, but the olive only reached the 5 cc marker on a Kupat Holim medicine measurement cup, thus this is an upper limit to its volume. My estimate is that its more likely 3-4 cc. Thus the rabbinic model of an olive (>25 cc) must have been a super-olive! If an olive was a perfect sphere, its radius would need to be 1.8 cm, and thus an olive shaped olive would need to be longer than 3.6 cm. If an egg and an olive had the same profile, than a rabbinic olive would need to be 74% of the length of a #1 Israeli egg (6 cm), or 4.5 cm long. So now my question is, on what basis did the modern poskim arrive at their figures? Did they figure that ancient agriculture was more successful than modern? Perhaps the poskim lived in a land of super-olives, i.e. olives almost the size of eggs? Or did they not know geometry? Or are they using a safety factor to build a fence around the torah?

I offered the following response

Many have noticed the problem that Re'uven has described so clearly. My response is my own and not based on the explanations given by others - which seem to me to be rather forced (such as the "super-olive" posited by Re'uven. Since my response is my own it is to be seen as purely academic with no halakhic implications whatsoever.

Despite the fact that biblical and rabbinic measurements seem to be based on the human body, there was a definite system of correlation between them all - length, area, volume, weight. The basic unit of measurement is the "finger", which indicates the breadth of the thumb at its knuckle. Then there is the "span" which indicates the distance between the thumb and the little finger when the hand is spread to its greatest capacity. The "cubit" measures the distance from the elbow to the furthest extremity of the middle finger. As far as correlation is concerned: there are 24 "fingers" in a "cubit". (To me it is clear that there are two stages in development here, but we can accept this just as we accept today that there are 12 "inches" in a foot - a standard foot, not your own private foot.)

Thus the most basic unit of all measurement is the "finger", but let us refer to the "cubit" for the sake of our discussion. The minimum volume of water in a mikveh is set at 1 cubit by one cubit by three cubits high (three cubic cubits), and this is to enable a person to stand upright and be completely covered by the water. All other measurements of volume are derived from this capacity. Later on there was a discussion as to whether the height of three cubits included the head or not. This is a clear indication that the basic measurement - the expected height of an average human being - had gone awry. We are gradually getting taller. Even since the middle ages only we can see the difference: one can see in European museums (such as the Tower of London) suits of armour that some healthy teenagers would not be able to get into nowadays that belonged in their time to fully developed men of battle!

Thus, if we maintain the cubit at its "standard" measurement (more or less the equivalent of 48 centimetres) we would find an expected height for the average human being at around 144 centimetres (four foot eight and one half inches)! We are gradually getting taller - but eggs and olives are not gradually getting bigger in proportion, and thus the whole system of intercorrelation breaks down - as Re'uven has discovered.

Another participant reminded us of the story of the spies and their bunch of grapes that were so large they needed two people to carry them: if the people of the times were so small that a bunch of grapes appeared to be too much for one man to carry, then maybe olives appeared to be much larger as well? Even if the people were not that small, a land that could grow giant-sized grapes could grow big olives, I would think?

Nevertheless, it seems quite reasonable that a modern Conservative approach to the issue should be to reject the maximalist approach since if does not answer to the biological and botanic data that we have available. Therefore, most people now accept that the amount of 80 cc's describes the amount of a revi'it and is the minimal amount of wine that one should drink in order to fulfill the mitzvah of kiddush. Furthermore, this minimal amount should be drunk more or less in one go; at any rate it should not be spread out over the whole meal!


As part of our discussion in the previous shiur I quoted the comment of Ibn-Ezra on Genesis 2:2:

There are some who hold that the days were created as well and the task [of creation] was completed with the creation of the seventh day. (This is a weak explanation.) There are others who say that the [enclitic] letter bet [translated 'on' the seventh day] means 'before' [or 'by'], as in ... "by the first day you shall cease all leaven" [Exodus 12:15]. But why do we need all this bother? Completion of an act is not the act itself: it is as if it says He did not perform an action [on the seventh day]

Bayla Singer writes:

Is this the basis for the allowance I have been told of, that if one has begun a journey, one may continue it into Shabbat as long as it is not interrupted?

I respond

I don't know where you heard that one may journey on Shabbat! Without going into details here let me say very broadly that travelling (on foot) is permitted within the confines of one's town but not outside the town's boundaries. Travelling outside this area is not permitted regardless of whether one starts the journey on Shabbat or just continues it. The only exception that I can think of is that of a person travelling on a steamship: they are permitted to remain on the ship during Shabbat provided that they remain on board the ship until after Shabbat. (The same would apply in theory to any other mode of transport, but it would be very inconvenient to remain in a bus or airplane throughout Shabbat!)

Bayla also writes:

Personally, I think the explanation concerning the creation of the seventh day is not weak, but rather very strong! It had struck me, this past Shabbat, "Why bother creating a seventh day? HaShem surely doesn't 'need' to rest! This is purely a gift to humanity!"

I respond:

The comment that "this is a weak explanation" is not mine, but Ibn-Ezra's!