Wow! I wrote to Finish (the makers of Jet Dry) and asked them how they would recommend removing the surfactant left behind from the rinse agent - and I heard back in one day! What nice people... Hermit was dead-on!
They suggested using a 50/50 mixture of distilled vinegar and water to soak the Jet Dry teated dishes to remove the surfactant coating.
I used straight Heintz distilled vinegar (5% acidity). I gave the glasses about a 90 minute soak (probably way overkill). I tested a vinegar-treated glass and a glass washed in the dishwasher with Jet Dry countless times over several years. I poured two bottles of Lagunitas Brown Shugga (a beer that has blown my mind with its head-retention capabilities on tap... I've seen a 25oz glass keep a 1/4" foam head till it was gone... which took probably 90 minutes) into the glasses, built a nice foam head, then set a timer and periodically checked back.
The end result? The vinegar-treated glasses had a 60-75% better head retention than my plain ol' dishwasher-washed glasses. It worked!
The head retention, while much improved, was less than I was hoping for: the 90 minute wonder. I wondered if my hand-washing dish soap was adversely affecting things. Not being able to go through five bottles of Brown Shugga, though, I resorted to a simple "salt" test as described in the "Dishwasher/Enemy" thread.
I checked a vinegar-treated glass, a long-since handwashed glass that was re-washed with a new detergent (in case my hand washing soap was part of the problem) and for control, another beer glass that had been dishwashered and jet dried many times over the years. All three stuck the salt evenly like the glass was perfectly clean.
My conclusion? The salt test can indicate if you have a very dirty glass (e.g. someone who never uses soap on beer glasses might build up other strange deposits over time). But it will not reveal the presence of rinse-agent surfactants (i.e. Jet Dry), which has definitely played a big roll in hampering my glasswares' head retention.
For those who ask "does any of this matter?"... it depends. This season Brown Shugga has shown up at several joints around my town. I've had it in glasses that lose their head in 5 minutes and I've had it in glasses that keep the foam until it's gone. Make your own call. For me that creamy foam head does more to give the perception of thick mouthfeel than the actual dextrin content does... and I love a thick beer. A friend of mine really dislikes "nitro" pours for exactly the same reason. Beauty is in the eye (and mouth) of the beer-holder. Do what's right for you!
In the mean time I have to figure out how to vinegar treat something like 30 pint-sized logo glasses... Cheers, everyone!
