I drink coffee after boiling water and mixing it in the mug. The mug stays hot for a while and then I start drinking it. I have been crocheting for a while and I thought I might as well make a coffee cozy with wool. But I am wondering if it is okay to use wool with a mug that gets so hot that I can't even hold it.

What is the highest temperature that wool can sustain?

  • 5
    Wool will take temperatures substantially higher than that. Enjoy your hot coffee.
    – fixer1234
    Nov 6, 2019 at 17:04
  • Just be sure its not synthetic.
    – rebusB
    Nov 8, 2019 at 19:51
  • @rebusB acrylic crochet can certainly handle being wrapped round containers of hot drinks
    – Chris H
    Nov 21, 2019 at 10:50
  • @ChrisH - Yes its melting point is higher than that of boiling water, but it can still melt if exposed to enough heat unlike natural fiber. Plus it feels awful IMHO... but technically you are right, its safe for coffee.
    – rebusB
    Nov 22, 2019 at 15:21
  • @rebusB rather than melting I'd be more concerned about it losing its shape, like a sort of anti-ironing, especially if it gets splashed. Resistance to coffee staining would also be desirable
    – Chris H
    Nov 22, 2019 at 16:42

1 Answer 1


In addition to being extremely insulative, wool is ideal for something like a coffee cozy because it is stable in the presence of a fairly high degree of applied heat, it is un-meltable, and it has a very high combustion point.

For a practical example of wool’s ability to withstand heat, when pressing wool, the recommended iron setting is 148 °C (300 °F), which is well above the boiling point of water, which is 100 °C (212 °F).

Measurements determining flame retardance show that wool has an “ignition temperature” of 570-600°C (1058-1112°F), and does not melt at any temperature. (See table below.) This is very favorable in comparison to other fibers, for any application near a non-flame heat source.

So enjoy your coffee cozy with peace of mind!


  • 1
    But make the cozy thick enough, so that your skin doesn't accidentally come into contact with the mug through potential gaps.
    – Joachim
    Nov 19, 2019 at 19:58
  • @Joachim felting it might help with that, right?
    – Morgen
    Dec 29, 2021 at 18:48

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