Answer by Rabbi Chaim Hillel Raskin – Rov in Kfar Chabad Beis, Israel:
It customary to refrain from eating meat and drinking wine in proximity to Tisha B’Av in order to reduce in joy during these days and focus on the churban. This also commemorates the absence of the wine of the nesachim (wine poured into a channel on the mizbeiach) and the meat of the korbanos.
The Sephardic custom is to refrain only during the week of Tisha B’Av, while the Ashkenazic custom is to refrain from Rosh Chodesh Av (except on Shabbos or at a seudas mitva which is another topic, and see issue 420 regarding havdala). This custom has the status of a neder accepted by our ancestors, which obligates us as well.
Some poskim hold that the prohibition doesn’t apply to wine in a mixture, especially since wine in a mixture is invalid for the nesachim. Others hold that one should refrain even from such wine.
One reason is that one might mistakenly drink the wine when handling it (a concern that wouldn’t apply if the food was made before the nine days). Secondly, some explain that since the custom was to refrain, it is a part of the neder, and this is the accepted Halacha.
In practice, we do not eat dishes that contain wine unless the wine is less than a 60th of the dish, rendering its taste unnoticeable. One may taste the dish to determine if it has a taste of wine or meat since he isn’t doing so for enjoyment.
Children under nine may eat dishes that contain wine, since it is disputed if children are obligated to mourn, and it is a further dispute whether wine in a dish is a problem. These two doubts are thus combined to allow children regarding this rabbinic prohibition.
Cooking pareve food in fleishig utensils is permitted. Wine vinegar doesn’t cause joy and wasn’t a part of the minhag, and is thus permitted.
Published in the Weekly Farbrengen email by Merkas Anash. See Sources
I think there is a difference between a siyum versus a bris/pidyon haben?
Can somebody provide source for last sentence in second paragraph?
Thank you.