- Kosher wine must be handled throughout production by a Sabbath-observant Jew. This includes all steps from harvesting to bottling, and even serving, unless the wine is meshuval (see below). Increasingly, many kosher wineries are owned by nonobservant Jews, or even non-Jews, which would seem problematic, but can be worked around if the winery owner overseeing the process has an observant worker remove samples for their consumption and assessment throughout the process.
- All ingredients used in production must be kosher. Wine may have yeast (often derived from bread or grains) added to aid the fermentation process; yeast used in kosher for Passover wine must come from another source, such as fruit. Common fining agents like gelatin or casein, which are used to clarify and stabilize the wine, are prohibited in kosher wines, since they are derived from pork or beef animal sources and would pose concern when paired with meat or dairy foods under kashrut law.
- Kosher wine must be certified. True kosher wine will have a hechsher, or seal of approval from a kosher supervising agency, or specially ordained rabbi; this is often in the form of a signature on the back of the label.
- Some kosher wine is mevushal. This means that the wine has been pasteurized at a temperature of 194ºF or higher and can be opened and served to observant Jews by anyone without sullying its kosher status. Some wine connoisseurs feel that the heating process damages the wine's flavor and its aging potential; increasingly, flash pasteurization, which is less detrimental, is being used.