In the last installment, we discussed the prohibition of Yayin Nesech (wine touched by an idolater). Cooked, or mevushal, wine is not subject to the prohibition of Yayin Nesech, but there are various opinions as to what temperature halachically constitutes “cooking”. The main opinions and their sources will be presented in this installment.

The Gemara (Masechta Avodah Zara 30a), commenting on the Mishna 29b’s statement that wine of a non-Jew is prohibited, says:

Shmuel and Avleit (Rashi: He was an idol worshipper.) were sitting together and they were served cooked wine. Avleit (concerned that he should not make the wine non-kosher) removed his hands (from the space near the wine). Shmuel then said to him (that it was not necessary for him to refrain from touching the wine since) the Rabbis taught that cooked wine is not subject to the prohibition of Yayin Nesech.

The Ran’s1 commentary on the Rif2 quotes the Raavad in the name of Rav Hai Gaon3 that as soon as the wine boils it is considered cooked. He then quotes the Ramban4 that the wine is considered cooked when some wine (evaporates and) begins missing some of its quantity. The Ran (as well as the Rashba5 ) concludes that maybe there is no argument, as both criteria are the same, for when it boils, it also evaporates. The Rosh6 only brings the first opinion (as he probably did not see the second opinion) and he compares it to the laws of cooking on Shabbos where the criteria is “Yad Soledes Bo”, (a hand will be scalded [removed instinctively] in this water temperature). There are various opinions on the appropriate temperature for this criteria, ranging from 112-160°F.

(The Rosh then goes into a discussion as to whether the reason for this prohibition is to discourage social drinking and possible relationships between Jews and non-Jews, or if it is based on the laws of sacrifice in the Temple and the prohibitions of idol worship. There is also a lengthy discussion by many commentaries on this issue, as well as understanding why cooked wine is permitted. Some say because it degrades the wine, some say because it is unusual to cook it, and some say because the original source of the prohibition was only on uncooked wine. This article will not be able to clarify these questions, I am merely bringing them up to whet your appetite to continue researching, and gain insight into some of the later mentioned opinions.)

The opinions mentioned above are the basis of the Bais Yosef’s7 decision in the Shulchan Oruch8 : When is it considered cooked wine? When it boils on the fire. The Shach9 , in Sifsei Cohen, his commentary on the Shulchan Oruch, then comments: When it lessens its quantity (evaporates), and he quotes this from the Rashba and the Ran.

In today’s wine making industry the wine, or more precisely the grape juice, is pasteurized shortly after it is squeezed and fermentation is caused by the introduction of commercial yeast. Pasteurization at this stage helps ensure that each bottle of wine in the production will taste the same, giving a consistent experience to consumers.

In order for the grapes achieve optimum quality each year, specific levels of moisture, sunlight and temperature are required. If these are higher or lower than the ideal, the fruit will not reach optimum quality. Consequently, the quality of the wine suffers, as the acidity level or sweetness level (brix percentage) of the grapes was not optimal.

Hashem, in His unlimited kindness and wisdom, created grapes with the quality of carrying its own (ambient) yeast. This is sometimes called the grapes’ bloom, or blush. This yeast is what causes the grape juice to ferment (and bubble), turning its sugar (sweetness) into alcohol. This should not be confused with the sweetness imparted in some wines. That sweet taste is what remains when the fermentation process is stopped before all of the sugar is converted into alcohol.

In the mid-19th century, a famous scientist, Mr. Louis Pasteur discovered that there were many living organism that could spoil or ferment the wine. In 1856, Pasteur was called to investigate why the wine of a local vintner was spoiling. He came up with the discovery that bacteria is a living organism and, therefore, if one would cook the grape juice to 60 – 100°C (140 – 212°F), it would kill all of the bacteria. Afterwards, if the vintner wanted to ferment the wine, he would have to introduce new, cultured yeast in order to turn the juice into wine.

This idea of killing the bacteria (and introducing yeast) is widespread in the wine and dairy industries, as well as the production of other fermented products. It is also the foundation of food safety practiced in most companies today to help control the spread of unwanted bacteria and contribute greatly to the shelf life of products.

The standard procedure in the wine industry today is to pasteurize all of the grape juice to 165°F and then add yeast, ensuring that only healthy bacteria grows and that all of the wine has a uniform taste. (Even after heating it to 165°F some of the bacteria can possibly reawaken during fermentation; therefore, some scientists recommend heating it to 212°F.) Some smaller vintners do not pasteurize their juice and choose to monitor it carefully and add or change chemical additives as needed.

Due to the serious prohibition of Yayin Nesech it is clearly easier to use cooked wine, since the wine might be handled by non-Shomer Shabbos Jews and even by, l’havdil, non-Jews; however it is considered more mehudar by some to use uncooked wine for Kiddush and especially for the Pesach Seder.

Reb Moshe Feinstein concluded1 that grape juice cooked to 165°F is considered cooked wine. He explains that Rav Hai Gaon’s opinion that as soon as it is boiled it is considered cooking is similar to the laws of Shabbos where it is considered cooking at the temperature of Yad Soledes Bo. He further says that evaporating also starts at that time. Later on, in his fourth sefer on Even HaEzer, Reb Moshe adds a few words towards the end of siman 108 saying the juice must reach 175°F to be considered mevushal, but he does not explain why he changed the requirement from 165°F to 175°F.

The exact temperature that wine boils depends on the altitude, as well as the percent of alcohol in the wine. As noted, wine boils at a lower temperature than water and, therefore, a mixture with 12% alcohol would boil later than wine with 16% alcohol. Those who accept a lower temperature for mevushal would probably point to distilling where cooking starts at a lower temperature. It is well known that the Tzelemer Rov, OB”M, (who used to certify Kedem and Royal wines) opined that wine must be heated to 190°F in order to be considered mevushal. This policy has been adopted by Kedem and many other wineries. The OK requires a minimum temperature of 86°C (186.8°F).

The relatively recent innovations of ultra- and flash-pasteurization, where the juice is pasteurized at different heat levels for a few seconds and immediately cooled, helps minimize the degradation caused by pasteurization. Since pasteurization is done in a closed, pressurized system, no vapor can leak into the atmosphere and evaporate. The halachic question is whether this affects the Ramban’s opinion that the liquid must lessen in quantity to be considered cooked.

The widespread use of ultra- and flash-pasteurization in closed loop pressurized systems throughout the wine industry has introduced a new set of questions as to whether the original intention of cooking the wine, outlined in the Gemara, has been preserved.

Rav Elyashiv, OB”M, questioned whether cooking wine is considered “an uncommon occurrence”, since one of the opinions permitting cooked wine was based on the fact that most wine at the time was uncooked. Since pasteurization is now the norm in the grape juice and wine industry, Rav Elyashiv questioned whether cooking could still be considered a heter to avoid Yayin Nesech.

Rav Shlomo Zalman Auerbach, OB”M, questioned11 whether the taste is changed during the cooking process. The heter for cooked wine, according to some opinions, is due to the inferior quality of the wine once it was cooked. Today, when the cooking does not noticeably degrade the wine, and some of the highest rated kosher wines are mevushal, the heter might not apply.

Rav Ben Tzion Abba Shaul argues12 that the wine must evaporate in order to be considered mevushal. The lack of evaporation in a closed loop system could invalidate the heter.

Those that permit closed loop pasteurization would argue that when the pasteurization loop is sealed, it merely forces the evaporated gases to revert to liquid. The liquid really is cooked to the level of evaporation, yet the plumbing system and technology forces the evaporation to reincorporate into the mixture and revert to a liquid state. The OK does not allow a fully closed system; there must be a way for some steam to escape. As for the lack of degradation and current commonality of pasteurization, the original takana was made only to prohibit uncooked wine. It never stipulated that the decree would need to be altered if time and circumstances changed and cooking became common.

Some bottles of kosher wine bear the designation “mefustar” (pasteurized). Those who follow the p’sak of Rav Elyashiv, Rav Auerbach or Rav Abba Shaul may not consider those wines to be mevushal according to halacha; however, Rav Ovadia Yosef, OB”M, argued13 that pasteurized wine is also considered mevushal.

Due to the serious prohibition of Yayin Nesech it is clearly easier to use cooked wine, since the wine might be handled by non-Shomer Shabbos Jews and even by, l’havdil, non-Jews; however it is considered more mehudar by some to use uncooked wine for Kiddush and especially for the Pesach Seder.

Our prophets tell us that wine is M’Sameach Elokim v’Anashim (it has the ability to bring much happiness to the Almighty as well as to people) if used properly. May we merit to experience much happiness and joy in our personal and family lives, as well as in our spiritual lives!

I hope this helped uncork some of the confusing opinions on kosher wine processing. This article is meant for educational purposes. As in all matters of Halacha, please consult with your local Orthodox rabbi to determine which opinions to follow.

Please send any questions or comments to [email protected]


In my previous article, I explained that crushed grapes can be purchased from a non-Jew if the grapes and the wine have not been separated. Once the juice begins flowing, the juice can become Yayin Nesech and must be handled by a Shomer Shabbos Jew.

I was asked by some of the readers to clarify this further.

When we buy grapes in a retail store, we usually check first to make sure that the grapes are not crushed. If we are buying a case of grapes, they usually come in a wooden crate which protects the grapes from becoming crushed. Even if the grapes were crushed, it would still not pose a Halachic difficulty, as the liquid would drain out from the holes of the crate. There would not be any leftover juice.

When a large wine producer purchases grapes, they are usually delivered in totes or trucks. A tote is usually a 6’x6’x6’ plastic container, which does not have drainage holes, allowing the  leaking juice to be used by the producer. Since all of the grapes are packed together in one container, and weigh about a half ton, the weight crushes the grapes and forces some of the liquid to come out. Of course, the same is true with a truckload of grapes.

Halachically, as long as the juice is mixed with the grapes and not separated at all, it is not considered wine. This is why the Mishna (Avodah Zara, Daf 55a) says that we are permitted to buy crushed grapes from a non-Jew.

As soon as the juice separates from the grapes it must be handled exclusively by a Shomer Shabbos Jew. The Gemara’s example is “piling it on a mound”. If all of the grapes (all of the solids) are piled high on the mound, leaving the liquid to flow nearby (even before it was sifted), this liquid is treated as wine.

Therefore, if the tote or truck is delivered by a non-Jew, it would be permissible (provided that it is handled properly in the field, as we will explain) since the grapes and juice have not separated. When the totes or truck are tipped in order to empty the grapes and juice into the processing machines, one may encounter a problem. When the tote or truck is tipped, naturally, the solids will pour out first. At the very end, there will be a few seconds where the container will only have the remnants of the liquid. At this second, the liquid can become Stam Yaynom, or non-kosher. Later, when this juice is poured on the grapes, the whole pile will become non-kosher. Therefore, only a Shomer Shabbos Jew should work the controls to tip the containers.

In addition, the mashgiach should make sure that the workers do not pour from one tote/truck to another at the field, as this can cause the same halachic problem. Lastly, the mashgiach must make sure that any grapes that are crushed and tested in the field are disposed of, as the juice is halachically considered wine. This can potentially cause all of the grapes to become non-kosher.


1. Rabbeinu Nissim (1320-1380) of Gerona, Spain.
2. Rabbi Yitzchok Alfasi (1013-1103). Lived in Algeria, Fez, and then Spain.
3. Headed the great Talmudic academy of Pumpedesia (now part of Baghdad, Iraq. Lived 939-1038.
4. The Nachmanides, Rabbi Moshe Ben Nachman (1194-1270) of Gerona, Spain.
5. Rabbi Shlomo ben Aderes (1235-1310) of Barcelona, Spain.
6. Rabbeinu Asher (1250-1327) of Cologne, Rome and then Toledo, Spain.
7. Rabbi Yosef Caro (1488-1575), author of the Shulchan Oruch, who lived in Spain, Portugal and Tzfas, Israel.
8. Yoreh Deah, Siman 123, S’if 3.
9. Reb Shabsi Cohen (1621-1662) of Lithuania, and then Moravia.
10. Igros Moshe, Yoreh Deah, volume 3, siman 31.
11. Minchas Shlomo, volume 1, number 25.
12. Ohr L’Tzion
12. Yabia Omer, Yoreh Deah vol. 8/15.