View Full Version : Propylene Glycol (PG), Airlocks, and Aging...

09-08-2014, 06:36 PM
I recently received my order of propylene glycol for experimental purposes. I emptied out all the vodka (mostly water after a few weeks) and refilled with PG. No problems so far. It is quite liquid, somewhat viscous, feels nice when I dribble some on my skin (it's used for this purpose in a LOT of products), tastes slightly sweet, but with a little bit of a burning sensation on my tongue that rapidly gives way to a pleasant warmth as it dissolves with my saliva. I cannot use my old syringe needles with it, and need to use at least a 15 gauge needle to pull it into the syringe quickly. It has no appreciable smell or taste (other than some sweetness) to it. And as far as I can tell it has no drawbacks to date. It is hygroscopic (it attracts and holds onto water molecules), and miscible (mixes in all proportions) in water, acetone and chloroform. We won't worry about the last two items though... It is a bacteriostatic agent that will not allow the bacteria to multiply, but will not kill them either.

It allows the air bubbles to freely flow in both directions. I would NOT use this for an active ferment as it would probably be forced out of the airlock as it is somewhat viscous and would not have the time to slide back down before the next bubble(s) send it up and out. Probably best as a long term bulk aging airlock filler rather than as an active ferment airlock filler.

I filled my airlocks with it, and have a piece of gauze held in place with a silicone band (rubber band but made from silicone) to keep dirt, dust, and insects out of my airlocks. So far one week out and no problems, other than a few pesky airlocks not sealing because of the airlocks rough edges. I filed them down, then flamed them lightly to smooth out all the surfaces and make a better seal with the drilled stopper.

I'll keep an eye on my experiments and report back once in a while, or when people ask.

09-08-2014, 09:49 PM
You can also use vegetable glycerine. Or a mix of the two.

After all, once the ferment has completed, there should only be occasional bubbles out from CO2 passing out the batch due to atmospheric pressure changes......

Bad airlock seals are the bain of our hobby. Badly moulded airlock stems. Bungs that are fractionally the wrong size or a material slightly too hard for the use we put it to.

Brewing buckets often have black grommets of a plastic type material that can be problematic. The home brew place.does replacements in pink rubber, which are softer/better seals....

Silicone ones (grommets and stoppers-various sizes bored through or solid) are available but a little more expensive........

Meh! You pays yer money and takes yer choice..........

09-09-2014, 09:37 PM
I thought about the Vegetable Glycerine as well, but ended up with PG as it is what I could find. Reason is that if I am feeling better by Oct 1st then I will be going on a trip to Utah for a month with my partner in our camper van. I just wanted to make sure my airlocks would not dry out while we were gone. So needed a solution, and this was the fastest and easiest available.

And those silicone grommets are what I have been eyeing, and will probably be purchasing in a couple weeks...

I always flush every component with plenty of vodka because we do live in a funky 101 year old former ranger station turned house. I can clean, but I can NEVER be certain of sterile with all the visible and invisible stuff ve have floating around all the time. Probably cleaner to do it outside in all reality... :rolleyes:

09-09-2014, 11:13 PM
Utah!$? Leave your vodka in Washington, It is barely legal here! Stop by in SLC and I can feed you some R&R.

09-10-2014, 02:00 AM
I'll probably stash a bottle of something away for the trip (my ferment of course!), where even I have to think about how to get it! We plan to stay away from cities and people, probably going to spend a week in Moab area alone. I've been overhauling a 1986 Chevy G20 Sportvan camper conversion from it's chewing gum & bailing wire, jerry-rigged, MacGuyvered 100,000 mile patchwork of writhing octopoid like web of wires, hoses, and tanks. Over 3 years it has slowly been converted to completely new electrical wiring, fuses, distribution panel, and LED lights, now all I need to do is get some solar panels and we can be off grid for 4 to 6 weeks at a time.

OK! After hijacking my own thread in 5 messages or less...

If we are going to be in SLC we might be able to drop in....

09-10-2014, 07:01 AM
Can't get many places in Utah without at least going through or around SLC. Moab area is really nice, as is the East side of Canyonlands. 9 Mile Canyon is really neat (near Price). Much to see, desert to alpine, in this state.

09-10-2014, 11:53 AM
Utah!$? Leave your vodka in Washington, It is barely legal here! Stop by in SLC and I can feed you some R&R.

This is why I recommend visiting sunny south Florida. The cops check to make sure you HAVE booze. They will direct you to the nearest drive through liquor store if you're found to be lacking.

We sell booze in gas stations here. Not beer, booze. Beer as well, but you know, we need to be gluten free. Lol

Sent from my galafreyan transdimensional communicator 100 years from now.

09-10-2014, 03:07 PM
Spent 5 plus years in Florida (St Pete) I was arrested several times for NOT having a beer between my knees while driving. Been there, done that.

09-10-2014, 03:29 PM
We need a sign saying "Alcoholic? Celiac? Then Florida is the place for you! Drive through liquor stores to drive by shootings, scorched earth gardening practices for those with allergies too!"

As for me, after my stint in the local ICU, I'm going from a drink or two a day to a few drinks on the weekends when I'm not working (The fact that I DON'T work and have eternal weekends is another matter). But seriously my drinking is down to 1 or 2 beers throughout the entire day, or a couple glasses of mead sipped on slowly, and only 2 or 3 days a week now. DANG!!!! Now I've got 6 gallons of mead that there is no way I can really drink for another year, and when it all get's ready I'll just have to gift my friends and neighbors, and age a few dozen bottles in our basement. But that is another story...

fatbloke: I'm thinking the PG might be a better choice if you regularly glug some into your ambrosia. I'm getting good at breaking seals and vacuums and making sure my liquids in my airlocks stay far far away from my ferments. Nasty little beasties those fruit flies, and the bacteria!!! The PG & VG are both bacteriostatic preventing the growth of organisms, but the VG is listed as a caloric food stuff, so it will prevent the growth, but not kill, and could provide food sources for the little basetard bacteria. The PG on the other hand has no caloric values, is bacteriostatic as well, so should in my minds eye provide a little more protection from nasties.... Make sense??

11-15-2014, 02:57 PM
OK, I have just pulled samples of all of my mead to date. All have been using PG in the airlocks while I was on a 5 week vacation. 7 out of 9 airlocks filled with PG not only stayed completely full (PG does not evaporate), but there were anywhere from 2 to 10 dead fruit flies in them. The other 2 out of 9 were without fruit flies only because I tried an experiment that seems to be working. There has been no growth of any organisms, nor any contamination of my mead to date. I will be emptying the fruit fly infested airlocks, taking samples for culturing them later then sterilize, refill and replace them.

The little experiment that seemed to work so well was to take a piece of gauze and use a silicone band to hold it in place. This not only lets the ferment still be able to outgas, but to prevent fruit flies as well as particulate matter of almost any size. This will not only guarantee that my mead has bacteriostatic protection with PG, but also against intrusions of other animal, vegetable or mineral nature from the gauze tied to the top of the S airlocks.