Quote Originally Posted by Ronald Moravec View Post
Don`t store colder that 68 F/20 C. or you can get precepitation.
I've done some storage testing with XTOL and one of the tests involved storing in refrigerator at 4C. This test didn't show any precipitation, but showed a great extension in shelf life. A test sample of 300 mL at the bottom of a 1 L bottle with air showed the same low level of oxidation than a 300 mL bottle without any air in room temp (23C). OTOH, the corresponding sample (300 mL in 1 L bottle with air) stored at room temperature showed a high level of oxidation.

Other samples at room temp had butane and they showed oxidation between the extremes.

The method of evaluation was visual inspection of yellowness, and developed test strips on film, scanned and measured for density in scanning software.

The result of the test was that if air cannot be squeezed out completely, putting it in a refrigerator can be surprisingly good way to slow down oxidation and increase shelf-life. After all, most chemical reactions slow down in cold.

There was no problems of precipitation. However, XTOL for this test was more dilute to speed up the expiration. Testing period was about 4 weeks IIRC.

If something would precipitate so easily in lower than 20C, say, at 10C, which I don't really believe, it would probably dissolve back when taken to 20C or over for processing.