Why pyranosides do not mutarotate?

For mutarotation, at least one hemiacetal group must be present in the sugar. Therefore, non-reducing sugars do not show mutarotation.

Why?

Consider the following reaction:

$$\ce{\beta-D{-glucose} + CH3OH + HCl -> \alpha-D{-glucopyranoside} + \beta-{D-glucopyranoside}}$$

Even though the pyranoside has an acetal group, the reaction is still reversible? Therefore, shouldn't pyranoside show mutarotation? Isn't the mechanism for the reversible reaction for acetal same as the one for hemiacetal?

In principle, the acetalisation reaction is indeed reversible. Typical conditions to reverse it would be to use $\ce{TsOH}$ or $\ce{PPTS}$ and water.