Till when may I wash for seudah shlishis?

#558. Till when may I wash for seudah shlishis?

We may not eat or drink once Shabbos is over until we have heard havdalah, unless we began a meal earlier by washing for bread; in that case we may continue the meal even after tzeis hakochavim (nightfall).

Poskim are divided about whether this prohibition applies from the beginning of bein hashmashos (twilight)—namely at shkiah (sundown)—or from tzeis hakochavim. There are many people who are lenient and do begin a meal after shkiah, but the primary halachic viewpoint is that the issur (prohibition) begins at shkiah.

There are poskim, though, who say that there’s room for leniency if one hadn’t eaten seudah shlishis (the third Shabbos meal) yet, and rule that it’s permissible to wash for bread even after shkiah due to the importance of this mitzvah. Others, on the other hand, maintain that starting a meal after shkiah is prohibited under any circumstance. One should therefore make sure to begin seudah shlishis before shkiah, or at least no later than immediately after shkiah*, thus avoiding any problems.

*) The exact amount of minutes differs according to location and season, a matter beyond the scope of this halachah.  #558

https://halacha2go.com?number=558

Practical Halacha: One minute a day. By Horav Yosef Yeshaya Braun, shlita, Mara D'asra and member of the Badatz of Crown Heights.