Kitchen Topology With Challah

Tonight is the start of Rosh Hashanah, the Jewish New Year. For me, holidays mean food, and for Rosh Hashanah the traditional treat is a round loaf of light and fluffy challah. Challah is an egg bread, usually shaped into a long braid. For the Jewish New Year, however, the loaf is round to symbolize the circular nature of the seasons. The bread is served with honey and apples for a sweet New Year.

Making challah–or any yeast bread–isn’t hard. The hard part, at least for me, is the braiding. Like most homeschoolers and other geek parents, we’ve done plenty of kitchen chemistry and even kitchen biology with the kids. But it occurred to me today as I set out the ingredients for our New Year’s challahs that we’re also doing kitchen math–in this case, kitchen topology.

Topology looks at weird shapes like Moebius strips and Klein bottles. It also includes the study of knots. In math, unlike sailing and rock climbing, knots are always made out of a continuous loop. And our round braided challah certainly fit the bill.

Here’s how to braid a round loaf:

1. Divide the dough into four parts and roll them into long skinny strands.
2. Arrange the strands like a tic-tac-toe board.
3. Weave the strands so that they go over-under.

1. Starting with the two strands pointing towards you, take the strand that is “under” and put it over the strand next to it. Continue going around the loaf putting the “under” strand over its neighbor.
2. There are now two new strands sticking out from each side of your loaf. Take the new “under” strand and go around in the opposite direction, putting the “under” strand over its neighbor.

1. Reverse direction and go around again in the same fashion. (If you have enough left, go around twice more, switching directions each time.) When finished, pinch the nearest ends together.
2. Now take the pinched-together ends of the loaf and pull them up to form a bowl. Holding onto to them, flip the loaf over.  Voila! You have a perfect round braided loaf.

Here’s a video to show you how to do the tricky part:

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