[Avodah] whole wheat challah

[Zev Sero via Avodah]

A few anecdotes:

(1) In 1949, on the ship from Europe to Australia, my father overheard
a passenger telling off his brother for smoking on Shabbos.  To which
the brother replied, "You're not such a tzadik either; I saw you eating
black bread on Shabbos".  My father repeats this as an example of what
happens when one doesn't know what's a melacha de'oraisa and what's a
mere culturally-dependent good practise.

(2) My grandfather AH lived with us, and in his final years his doctor
told him to eat only wholemeal bread, so the whole family switched to
wholemeal bread so we'd all be eating the same thing.  During that
period one of our regular Shabbos guests was a young woman who was just
becoming observant; one Shabbos she was at another home, and saw that
they ate white challah, and said "you must not be real Lubavitchers,
because Reb Arel has wholemeal challah".

(3) R Betzalel Wilshansky AH was one of the first bachurim from the
Kherson area, in the south of the Ukraine, to come to learn in
Lubavitch.  In those days yeshivos didn't have their own kitchens, and
bachurim ate "days" at various homes; having come such a distance to
the yeshivah, R Betzalel was invited to eat all his meals at the home
of the then-LR, the Rashab.  Although the Rebbe's household was fairly
well off by the standards of Russia at that time, like everyone else
they ate black bread during the week and white on Shabbos; but in
Kherson, which was a much richer region, they ate white bread all week
long.  So the Rebbe instructed his rebbetzin that Tzali Khersoner was
to be given white bread, because that's what he was used to.