The bag
The inside of the bag
A look at the bag with a 12 oz long neck (120 Minute IPA) in it.
I wanted to do so some by side temperature testing to see how much insulation this really provides. When choosing the beer, I wanted to err on the ironic side, so I chose a couple bottles of Deschutes 2014 Reserve Mirror Mirror Barley Wine. I really like the idea of showing up to a get-together with a great beer in what appears to be a paper bag. That’s probably because I am a generally hilarious person. 
Here’s the setup: The same two beers. One in the insulated bag the other sitting out with twoChefAlarm Thermometers (Hands On) tracking the beers. In this first shot, I have my ThermoWorks TempTest 1 showing the ambient temperature. The ambient temperature at the start of this test is 64 deg F. The beer in the bag is at 42 deg F and the un-insulated beer is 42.6 deg F.
Top of the bag.
After about 32 minutes the insulated beer is at 44.2 deg F. It has lost 2.2 deg or .068 degrees per minute. The un-insulated beer is at 47.1 deg F and has lost 4.5 degrees or .141 degrees per minute. That un-insulated beer is rising in temperature just over twice as fast.
After about 60 minutes the insulated beer is at 45.8 deg F. It has lost 3.8 deg or .063 degrees per minute. The un-insulated beer is at 49.8 deg F and has lost 7.2 degrees or .12 degrees per minute.