What does glatt kosher mean?

The lung check

After slaughter, the animal’s internal organs are checked for defects that would make it a treifah – an animal that could not have survived. The most common issue is an adhesion (sircha) on the lungs. The Shulchan Aruch rules that with almost any adhesion the animal is not kosher. The Rema, whose rulings Ashkenazim follow, permits adhesions that can be peeled off without leaving a hole, after a careful check.

Glatt and Beit Yosef

Meat from lungs with no adhesions at all is “glatt” or “chalak”. Over time many Ashkenazi communities also adopted glatt as their standard, as a stringency. Sephardim speak of “chalak Beit Yosef” – smooth according to Rabbi Yosef Karo, author of the Shulchan Aruch, whose standard is stricter still.

Glatt chicken?

Lung adhesions are checked only in cattle and sheep, so “glatt” technically does not apply to poultry or to dairy products. Labels that say so mean “strictly supervised”.

Why it matters to a buyer

Most kosher beef and lamb sold in North America, Europe and Israel today is glatt, so for many consumers the label simply signals the standard of the supervising agency. For Sephardim who follow the Shulchan Aruch, the relevant term is “Beit Yosef”, and Ashkenazi glatt meat is not always enough for them; Sephardi restaurants and butchers usually say so on their certificate.

Glatt is about meat, not about the restaurant

A restaurant that serves only glatt meat may still have other standards – for example, the supervision of vegetables for insects, of bread (pat Yisrael) or of dairy (chalav Yisrael). If a specific standard matters to you, look at the certificate or ask the supervising agency rather than relying on the one word.