Grape Juice Production
1. Production processes. To produce grape juice, grapes are detached from the vine and crushed to extract the juice. If the juice is to be used for wine, it would be allowed to advance to the fermenting stage, and over time, the yeasts would convert the sugars to alcohol. To produce grape juice, the natural fermenting process must be prevented so that it does not become alcoholic.
2. In the past, grape juice was not manufactured, as no method existed to prevent the natural fermentation process. The only way to have grape juice was to drink it right after it was squeezed. Due to a lack of refrigerating equipment, they did not have a way to keep the juice fresh and prevent spoilage.
3. Over time, they discovered that the fermentation process could be prevented by cooking, pasteurization, or the addition of chemicals such as bisulfites, which kill microbes and retain freshness, preventing the juice from spoiling quickly. With the invention of refrigerators, it became possible to keep the juice for a long time even after opening the bottle.
4. Thus, grape juice became established as an accepted alternative to wine for the bracha of HaGafen, for Kiddush, and for a kos shel bracha. However, new ways of producing grape juice raise multiple halachic shailos, which we will attempt to address, בעזהשי"ת.
Fit for Kiddush
5. Squeezed grapes. Grape juice is referred to in the Gemara as “יין מגתו” [lit., wine from its vat], i.e., fresh grape juice straight from the vat before undergoing any fermentation. It is fit for Kiddush, as the Gemara says (ב''ב דף צ''ו ע''א), One may squeeze a cluster of grapes on erev Shabbos and say Kiddush on it Shabbos night; this is paskened in Shulchan Aruch (או''ח סי' ער''ב ס''ב). Nevertheless, the best way to do the mitzva is to select good wine for Kiddush (שו''ע ס''ג), i.e., wine that was squeezed at least forty days earlier (מ''ב סק''ה).
6. Non-alcoholic. The posuk says about the wine poured onto the Mizbeiach, “הסך נסך שכר” (במדבר כ''ח, ז'). Chazal learn from here that to be fit for nesachim, wine has to be able to intoxicate. However, the Gemara says that even though יין מגתו does not intoxicate, it is acceptable b’dieved for nesachim, and anything acceptable b’dieved for nesachim may be used l’chatchila for Kiddush (גמ' שם).
7. Until forty days. Juice from grapes is called יין מגתו until forty days after squeezing; only then does it become intoxicating. From that point on, the wine may l’chatchila be used for nesachim, as it is now actual wine and not יין מגתו (רש''י ברכות דף כ''ז ע''א ד''ה ועל יין). One who drinks it violates the issur of entering the Mikdash after drinking, which is punishable by misa (כריתות דף י''ג ע''ב).
8. HaGafen. The bracha on יין מגתו, aka grape juice, is also Borei Pri HaGafen (שו''ע סי' ער''ב ס''ב).
