Can you explain what makes a wine kosher...or perhaps the question is why aren't all wines kosher? And what steps make wines kosher for passover?
Answer From Expert Roger Bohmrich MW
This is beyond my own area of expertise. I understand from producers of kosher wine and other sources that there are many criteria that must be met for a wine to be kosher. Only Sabbath-observant Jews are permitted to be involved in the winemaking process, from harvesting to bottling. All equipment and materials must be kosher, and, to meet the strictest requirements, no animal products (such as egg whites to fine or clarify the wine) can be employed.
"Kosher for Passover" wines have been kept free of grains, dough and bread.
If you would like to find out more and confirm these facts, I suggest you contact someone with specialized knowledge of this subject.