Marble Slab Paradox
the Fudge House, we were told, the first batch of the day seems
to take forever to get firm, but once a few batches of fudge have
warmed up the marble slab, the fudge begins to set faster.
seemed pretty strange to us that fudge would set faster on a warm
slab of marble than on a cold one. After all, as the fudge cools,
sugar molecules start coming out of solution and forming solid crystals.
Since crystallization is what turns fudge from liquid to solid,
shouldnt more rapid cooling lead to more rapid solidification?
solve this mystery, we talked to Dr. ZoeAnn Holmes, professor of
nutrition and food management at Oregon State University. She confirmed
the phenomenon and explained that when fudge cools slowly on a warm
slab, more crystals have a chance to form. With a higher number
of microcrystals, the sugar has more sites on which to crystallize,
and so crystallization ultimately happens faster.
comparison, fudge cooled quickly on a cold slab has less time to
form the tiny seed crystals that will grow as the fudge cools.
With fewer crystals to work with, the sugar in solution actually
takes longer to solidify.
What does this mean for the home fudge chef? Our experience is that
we get pretty eager for fudge once weve started cooking it,
and we hate having to wait for it to cool down to lukewarm before
beating it, as instructed in most recipes. A few of us have attempted
to help the cooling along by putting the hot fudge in the fridge.
But according to what we learned from Professor Holmes, instead
of helping to speed things along, this probably prolongs the time
it takes to reach the "beating" stage of fudgemaking.