I don't do tobacco anymore (funny considering that is how I started vaping) other than the occasional RY4. The only things I put in the fridge are my real flavors super concentrate flavorings (the owner said 12-18 month shelf life, or 3 - 4 years if stored in the fridge) since I have so many (and they go a long ways at 3.5% flavoring per recipe), and the bulk of my 100mg/ml nic in the freezer obv. A fridge would likely slow down the steeping process of a mixed juice I would think. All my mixed juices go in a cabinet in my Michigan cement block basement which stays a nice cool temp all year long.I say water bath rather than speed steep but I have found that using less flavoring in a DIY mix I get much more flavor than I had before. My last mix was a Turkish tobacco steeped at 130 F for six hours using less flavoring than I had previously. Very easy to tell it was a stronger flavor. I'm comparing this to a Turkish mixture that was mixed and put into a fridg. Maybe left in there a few months. At this time I'm amazed at the results, I should try both methods in the future.