
There’s no reason to cry over spilled milk, but there is a reason to cry over broken wine glasses. Those things can be expensive! If you’ve ever noticed the beginning of a crack in your glass, there might be a surprising reason why.
Rinsing incorrectly can crack wine glasses, and while that particular dish washing step might seem simple, it’s a bit more complicated than you think.
You probably want to get your wine glasses extra clean after a night cap (to avoid staining) or when switching between varieties. In that case, you might be tempted to turn up your water temperature for a scalding wash (my mom always said if your hands aren’t burning, your dishes aren’t clean). Your glasses, however, are susceptible to thermal shock, and that extremely hot water could cause cracking.
When a wine glass undergoes a rapid temperature change, thermal shock can occur. Hot water hits the inside of the glass, and it warms. But because glass is a poor heat conductor, the outer layer can stay cold or room temperature. The temperature differences between the inner and outer layers are what causes the cracking.
Thicker glasses are more susceptible to thermal shock. Because the inner and outer layers have more space between them, heat moves slower to the outside than with a thin glass. That longer period where the temperatures are different makes them more prone to shock.
The next time you’re washing your wine glasses, it might be best to make the water a bit more temperate (and maybe skip the detergent, too).