Well that's unfortunate. The crock pot I have is nice it's only maybe 3 years old has a digital dial and everything. On keep warm setting I've tested it with an oven thermomater think it's at least 150 maybe 145 at the lowest.
Only other thing I have that might work good is a big rice cooker that I don't think gets that hot have to test with the thermomater.
Of course I could just be patient put the bottle away in a dark cool place and just forget about it like most people do. Can be hard to be patient with new flavors I typically make really small batches only 8 mls at a time being that my aromamizer takes 6 and the rayon coils take about 2 when I presaturate prior to first vaping on a new tank.
Make 2 identical 8ml mixes, label them. Speed steep one, and closet steep the other one. I do this as I'm learning, I can then compare them over time.