Are separate glasses required for milk and meat?

Question

It seems to me that there are some interesting things which are done in virtually every kosher Jewish home that may have no basis in halachah. I think that having separate glasses for meat and dairy are unnecessary.

Is there a halachic requirement to have separate glasses?

Answer 1

There is a reason for it.

The Mechaber in OC 451:26 says:

כו. כלי זכוכית אפילו מכניסן לקיום ואפילו משתמש בהן בחמין אין צריכים שום הכשר שאינם בולעים ובשטיפה בעלמא סגי להו. הגה: ויש מחמירין ואומרים דכלי זכוכית אפילו הגעלה לא מהני להו וכן המנהג באשכנז ובמדינות אלו

My loose translation:

Glass vessels even if one stores in them and even if they were used for hot things do not require any hechsher, because they do not absorb, any rinsing is sufficient for them. The Rema says: and some are stringent that even Hagala does not work for them, and this is the custom in Germany and these regions.

See MB there that this applies lichatchilah even to glassware which is usually used with cold.

The above only refers to Pesach, where the psak generally follows a more strict opinion. (There is a discussion in the Acharonim about what the Ashkenazi minhag is by regular kashrut).

By regular kashrut there is certainly room to be lenient in some situations, but one would imagine it preferable for one to follow all opinions in his own home when there is no major financial cost in doing so.

As always ask your LOR for practical advice.

Answer 2

By way of background, one first needs to understand there is a difference of opinion between Ashkenazim and Sefaradim regarding the absorption and kashering of glass utensils.

Some poskim believe glass is hard and smooth (nonporous) therefore cannot absorb taste and doesn't require kashering. Others believe glass is similar to metals and absorbs taste, but maybe be kashered through hagalah (hot water). Others believe that since glass is made from sand, it is comparable to earthenware and cannot be kashered.

Ashkenazi poskim follow the strictest opinion for Pessah but many are lenient and permit kashering glass (if for instance meat fell into a hot milk glass). Sefaradim follow the first opinion that glass never needs kashering even for Pesach.

Once this is understood, there are two opinions regarding using one set of glass for meat and dairy

1. Some use one set of drinking glass for both meat and dairy meals (additional leniency: glass are not used for hot meat drinks, they are merely placed on the table) (Yabia Omer YD 4:5) - what I heard from my rav is that one needs to be careful when putting dirty milk glasses in the sink not to pour hot meat soup on them
2. Some Ashkenazim follow the strict opinion and have two set of glasses, now that glasses are cheap (Teshuvos v'Hanhagos 1:432, Tzitz Eliezer 9:26)

Everyone should ask his own rabbi how to proceed based on his personal circumstances.

Source: R Binyamin Forst's the kosher kitchen and here for R Chaim Pinchas Scheinberg's views.

Answer 3

I heard from a Rabbi, a popular Halachah teacher in Bais Yaakov high schools, that while essentially one would be permitted to use the same glasses for milk and meat, nowadays it is not the custom for two reasons:

1) Glasses may be used for actual hot milk and meat. Or, they are often exposed to hot milk and meat in the dishwasher.

2) There is a concern that the glasses may not be washed properly, and there may be grease on the rim of the glass.

3) Glasses nowadays are cheap, and it is easy to have two sets.