No stupid question. There is something called an infared Temp Gun. You can lift the cover a bit "point and shoot" and it will read back. I haven't done temps on insulated soap in years. No need to. If I know we are going to have a cold night I just put over an extra blanket so the temp don't drop and cause soda ash.
Check Amazon, Ebay or Home Depo. I love the guns its easier than a thermometer.
Thx again - learned something new - low temps can cause soda ash. That must be why no soda ash since november. I must say this is great site as Ive learned so much from everyone- I have not posted much yet but have read a lot with troubleshooting my bloopers. And I understand frustration I see with people not doing research and wanting answers instantly. I am still newbie with soaping - researching for over year and soaping about 8/9 mths. One day I will give back as you guys do.