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Wort Aeration & How To Build A Free Pump

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One of my favorite aspects of home brewing is the ingenuity that can be used throughout the process. Some people have the finances to buy the biggest and best equipment, some like me do not. For me, the fun comes in when I can use some ingenuity to come up with a way to do something cheaper and easier to produce a better beer.
In my progression as a home brewer I reached the point of aeration.
"Yeast needs between 8 and 10 parts per million (ppm) of oxygen to properly reproduce in the lag phase. A level of 8 ppm is achievable using air alone (which is 21% oxygen), but achieving a higher level requires a tank of pure oxygen." (Brad Smith)
So 8 ppm is the ultimate goal of aeration without using pure oxygen. There are several great devices that are mass produced for this including aquarium pump builds, aeration pumps (pictured below), and siphon sprayers to name a few. My goal is to use some ingenuity instead of purchasing a product.

So what methods are out there where you don't have to buy anything?
A simple yet effective method is shaking and splashing the fermentor, which according to some, reaches that 8 ppm. A few tests conducted by Home Brew Talk members using Diffused Oxygen meters has shown that from shaking and splashing they only reached between 2.4-4.5 ppm. Another struggle people have with this is the physical ability to rock and splash and the fermentor.
So what is an effective way to pump air into the wort using household materials?
Using some ingenuity and reading Home Brew Talk got me to thinking about the Venturi effect.
The Venturi effect works by decreasing the cross sectional area of a pipe to increase the fluids speed (in that decreased area). The increase in speed creates a decrease in pressure in the restricted cross sectional area. This decrease in pressure acts like a vacuum and if a hole is in the decreased area it would suck up the fluid outside of the hole and combine it with the liquid. (http://en.wikipedia.org/wiki/File:Venturifixed2.PNG)

So if the siphon tube transferring the wort from the kettle to the fermentor has a Venturi device in it there would be a combination of air and wort that we are looking for.
So how do we build this from stuff laying around the house?
I took my vinyl siphon tubing that was attached to my auto siphon and I used two worm clamps. I simply drilled a hole in the vinyl tubing and used the worm clamps on either side of the hole to decrease the cross sectional area. The increased speed of the fluid through the decreased area lowers the pressure and creates the vacuum (pump).

So the next test was to see if this device truly used the Venturi effect.
I took a straw and shoved it in the drilled hole. I then ran water through the device, hearing the vacuum sucking in air through the straw. Next, I placed the straw in colored water and it sucked all of the water out of the cup. I filmed this experiment:
I have seen many methods used to create the Venturi effect by members of Home Brew Talk this method is what I found to be the most effective for me and it was free!
Many people have paid for a pump but this is a free way to pump air into your wort using the Venturi effect!
 
How about my Home Depot $0.69 plastic paint paddle?
5 minutes does the trick. Krausen's reliably within 12 hours.
If you include the cost of the electric drill then not so cheap:)
 
The Venturi effect is great - I simply added a plastic "T" in the middle of a piece of tubing that I use to drain into the fermenter. Wort flows in the top and out the bottom of the "T" and air is sucked in through the side hole.
Just be sure to put your thumb over the side hole when you first open the valve and start draining, then release once the wort is flowing.
 
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The plastic T is a great way of using the venturi effect. BVN, that is another viable option, I just like finding ways to make my life easier, while making great beer.
 
For years (probably 20 now) I have used a section of racking cane with several holes drilled in one end. That end is attached to the line (so there's about 6" of tube after the holes) and the wort passes through the chiller and into the fermenter. The holes allow a great deal of aeration as it passes by. The only caveat is you can't stick your thumb over the end to stop flow as it then turns into a sprinkler (same issue you have now).
Like you I have not tested dissolved O2 with this method, but my fermentations are completely acceptable.
 
Any idea as to the level of oxygen introduced using this method? You cited 8 ppm as being the target. Did you achieve that?
 
Great tutorial, thank you. DustBow mentioned a T fitting. Now i see it can be doubly useful - Pull a suction on the T to start the siphon without a self-priming cane, then leave the T open to aerate. A $1 T replaces the primer and pump.
 
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Fryrish, there is a chance for contamination since you are sucking air into the wort. From what I have read no one has had a contaminated batch using the venturi effect. If it is a concern then add an air filter like the ones used in the aeration pumps to the venturi opening and you will be all set!
 
I just poked a ton(20+) of holes with my digital thermometer into a spare hose near the top where it hooks into the kettle...
Sucks in ton of air through all those holes.
 
Whenever I use my auto-siphon, the point where the tubing connects to the bend is always loose until I fiddle with it and get it just right. I know it's introducing a lot of air - but I never use it on hot wort, just beer! I like the T-attachment idea. Heck, you could add an inch of tubing and put a little plastic valve on it, even.
 
@Fryish: My aeration consists of pouring my brew kettle from as high as I can lift it above my primary, then splashing the s**t out of it with my brew spoon... Can't think how the Venturi could be higher risk. I think the keys are sanitation, and not having fresh wort anywhere near where you crush or store your grain.
 
I use a air pump designed for a air mattress. I spray the inside with star-san cover the intake with a towel soaked in star-san.
 
With no more resistance than it has you could probably route the air intake in through the same type of filter people use their airpumps with. Might take a little ingenuity to get the connection done but it should be doable.
 
@aarong
the very same air that is being sucked in to the wort is being sucked into the wort when you shake or stir or use a pump. No need to worry .
I use a metal paint stirrer on a drill myself but I like this idea and do plan to use it next brew.
I used to use a aquarium pump an a large stone also just stirred it good with my flat paddle and that worked great .
But in the end it is all the same air although doing it outside would be cleaner air than in home by far.
 
That's interesting, this is the same concept as a water aspirator to create a vacuum (chemistry lab). I would love to see someone test this versus splashing for dissolved oxygen.
 
What about leaving the siphon intake right at the point where it allows some air in but still takes in mostly liquid? It bubbles in plenty of air & still siphons just fine.
 
I also use a venturi tube to aerate my wort on the way to the fermenter. What I did was take a piece of racking cane and slowly heated it over a gas flame until it became malleable. I then pulled the racking cane (like taffy) until it formed into an hourglass shape. After it cooled I drilled a teeny tiny hole into the tube a little bit past the narrowest part of the hourglass. It easily attaches to 2 sections of 3/8ID tube. It absolutely screams while sucking in air! Sound like a little siren.
 
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Those are all awesome ideas. I definitely like the plastic T. I tried to create the hourglass by heating plastic and pulling it. I formed the hour glass shape but didn't have much luck with it. Most likely I was not doing it correctly. I would be a little nervous sanitizing the hand pump maybe because the one I use for an air mattress has a large diameter tube and ridges which would be difficult to clean. I would definitely like to know how much Dissolved Oxygen these devices make!
 
Cool idea. Do you think this gets more air in than pouring the wort through my strainer? I normally just lift my kettle and pour it through my strainer sitting on top of the fermenter bucket. I quit using the cane because I was worried about not getting air into the beer.
 
Seems like a bit of a dice roll for contamination, but a cheap air filter will take care of that. Even w/o it, the odds are in your favor. Nice idea.
 
Just tried it on today's brew and it worked like a charm. I'd imagine there's less risk of contamination with this method relative to what I usually do: using an immersion blender with a whisk attachment I whip in (the same) air.
 
I keep looking at my "double bubble" airlock and seeing 2 perfect venturi chambers. It would be pretty easy to stick one into a carboy cap (or inline with tubing) and aerate wort on the way through to the fermenter (carboy or bucket) but just where should little holes be drilled?
What's with the rolex ads drasdena?
 
I usually pour bucket to bucket a few times with adequate results in 36 to 48 hours. This time I used the plastic T method. Using a 7 gram package of rehydrated Munton's Premium Gold yeast at 64f. I had a foamy head in 6 hours and bubbling airlock in less than 18 hours. Awesome, thanks for the tip aarong!
 
Tried this this weekend. Works great bubbling away in about 8 hours. (Might have been sooner but I went to bed..) Thanks for the idea. I would also love to see the 02 tested just get the science confirmed.
 
3 or 4 minutes with a sanitized cup, taking up and then pouring back the wort from 8 or 12 inches from the surface. Scoop some up, pour it back in. Scoop some up, poor it back in. Scoop some up, pour it back in, repeat times a hundred. Nothing expensive, technical or crafty but it works. But then again, I'm a newbie so stay tuned...
 
I simply poor the wort through a sanitized fryer screen sitting on top of my fermenting bucket. I'm sure this introduces tons of oxygen to the wort.
 
I tried this, and it worked perfectly when I tested it with water, but when I tried it with chilled wort, it started spraying out the end of the straw. Any ideas what went wrong?
 
Nice little article! Thanks! I'm a newbie so all of these great articles are very informative to me. I'm interested in using the plastic T method. Where can I pick one up? LHBS or hardware shop? Anyone have a link that they could share?
 
@bvn:
That's exactly what I did! I had the drill; the paint stirrer was a couple of bucks, and works a treat!! I still need higher attenuation, so a stir-plate next!
 
Great idea, I use a strainer and have not had a problem, but the closer to perfect we can be the better the beer.I will try this method in the future , thanks for the article.
 
This is awesome! Mine didn't work at first, but then I just tightened the clamps down and bingo! I just tested it out with water today, but I'm psyched to use it on my next beer.
 
FYI - for those that are having trouble getting this to suck air in...the venturi needs to be below and downstream of the highest point in the hose(especially if you are pumping) otherwise it will be at a higher pressure than the atmosphere and will leak rather than suck.
 
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