Why does my sous vide stick have scale or white marks on it?

White marks are usually limescale or mineral residue from heated water, and they are common on appliances used regularly in hard-water areas. The marks are usually a cleaning issue, but you should still check that the build-up has not affected the product’s operation.

What to check

1. Switch the unit off, unplug it and let it cool.
2. Inspect the water-contact area, display edge and lower section for rough deposits or crusty build-up.
3. Wipe the affected area gently with a soft cloth and a mild cleaning solution suitable for household appliances.
4. Dry the unit fully before using it again.
5. If the scale has become thick, repeat cleaning rather than scraping it away with a hard tool.

What the result means

If the marks reduce after cleaning, the issue was normal mineral build-up. If the deposits stay rough, spread quickly or seem to hide damage, the appliance may need closer inspection.

When to stop using it

Stop using the sous vide stick if the scale is accompanied by cracks, leaks, heat damage or an odd smell. If the issue remains unresolved or safe use is uncertain, contact the retailer or store where the product was purchased.