Wort Aeration & How To Build A Free Pump
Posted Feb 06th 2013 | By:
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!
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diy, tutorial, experiment, wort, aeration, wort aeration, aeration pump, pump, venturi, venturi effect, free