Yes when there are large fixed costs to expanding production, that will happen more slowly, after determining that the high demand isn't just a short term spike.

It's not like wheat, where you just can just plant more at marginal cost (I'm sure someone in farming will now explain why that isn't exactly true either).

I'm not super familiar with farming, but I'm pretty sure there is an upper bound on how much wheat you can plant dictated by the amount of land you own.