So I recently got of one of these air stills... After reading a few of the threads here I see lots of folks who were adding digital controls to their brand name air stills, along with other "mods" It seems as though this one has answered many of the issues that others were trying to solve with various controllers and such. Larger capacity, and digital control over temp, a timer, and full power fan. So now comes the fun part... I wanted to really push the limits with this little machine and see what can really be done with it. I plan on updating this post as I go through the learning curve. So far, I have experimented with all steps of the process:
Boiling a mash: First I wanted to see if I could boil cracked corn in it since that always seems to be one of the biggest PITA issues. setting the controller at 104°C I tried to boil 2lbs of cracked corn in 1 gallon of water, I stirred the corn in and it hydrated nicely and seemed to have no issue hitting a boil even with the top off (fan unplugged) The only issue is that without continuous stirring, the Overtemp Safety engages and it shuts itself off, it does boil if you are stirring and keeping the grain moving. This is not the most ideal as it is alot of work and attention for such a small amount of volume, although 1.6 gallons is better than the OG airstill that can only hold a couple of liters.
Traditional Mash: Here is where I got really excited about this being a much more useful tool. I was able to put in about 2/3 full of water, set the temp to about 75°C (170°F). it beeps when it is up to temp, then I stirred in a couple of lbs of crushed grain, which dropped the temp to about 150°F, I reset the still to 65°C (150°F) added amylase enzyme and let it sit for 45 minutes (the timer can be set for this to remind you). I stirred about once every 10 minutes and had no issues. The temp controller held the mash at exactly the predicted temp (verified with a separate thermometer in the mash). I think this is a really cool overlooked application especially when you are trying to micro batch things or see what flavors you get from particular grains or blends before going large-scale.
Fermenting: WHAT? You say. YES fermenting! after mashing I added some sugar and nutrient then set the temp for 30°C (85°F) this is the LOWEST setting, but exactly where I like to ferment. After about an hour or so, the temp had fallen to the desired range, (once again signaled by a beep). I added yeast, and set the built in timer for 99h 59m which was the maximum time you can set the timer for, I put a few drops of silcone anti-foam, placed the lid on loosely and let 'er rip. It held a solid 85° the whole time, while the ambient temp was about 65°F which would have been way too cool to finish fermentation completely. After completion of the ferment, I was able to quickly pour the wort through a strainer into a bucket, rinse out the good ol' air still, refill with the strained wort, kick the temp back up to 101°C and do a stripping run.
Distilling: Ok so this is where I am at now... I have done a few test runs and it seems that since this is officially intended for water , the high limit is 105°C (220°F) to get a hard rolling boil for water distillation. Obviously I have no interest in distilling water, so for alcohol distillation it seems like 100-102°C is a more realistic range. As others here have said, with these stills, SLOWER IS BETTER. I tried to re-distill an absinthe recipe that was made with 151 and botanicals (more on that later), I turned it on and left it at the default setting 105°C and it ran through super fast, and was weaker than the 40% I had diluted to, not to mention it ended up scorching the oils in the still and tasted/smelled slightly burnt. I plan to do more with this, another absinthe, and a couple of gin recipes I want to try. I want to find the right setting to get a good 3hour-ish run and discernible cuts. I will update this post when I do....