One of the most important factors in making great beer is providing the optimum conditions for your yeast to do their job. In the last newsletter we covered pitching the optimum amount of healthy, vital yeast. This time we will cover proper aeration of the wort.
When you pitch yeast into your wort, the first thing the yeast does is start absorbing oxygen for their long meal ahead. The benefit of optimum oxygen aeration is promoting the growth and reproduction of yeast. With proper growth and reproduction you beer will start fermentation quicker, finish fermentation quicker, and with less off flavors being produced because your yeast is happy and healthy.
What is the proper amount of oxygen? Most breweries shoot for 8-10 parts per million of oxygen in their chilled wort. 5 ppm is considered the bare minimum for proper yeast growth. Oxygen saturation between 5 and 8 ppm is attainable just using air but if you want to get to 10 ppm then direct injection of pure oxygen is necessary.
Most home brewers use some form of agitation to introduce oxygen into their wort. They might stir the wort very vigorously, shake the fermenter vigorously, or splash the wort from bucket to bucket. Some home brewers buy the Mix and Stir drill attachment and use their drill to give their wort aeration some serious power. Stainless Steel Mixer
Even though agitation can be very effective many home brewers don’t agitate long enough. The best advice I can give you is once you think you have agitated enough. Double it.
Another way of introducing oxygen is to use an aquarium air pump, an inline filter, and a .2 micron stone. 30 minutes of running the pump should get you to around 8 ppm of oxygen.
Studies have shown that the best way to get to the Holy Grail of 10 ppm of oxygen is to inject pure oxygen. In worts of 1.060 or less, a 60 second shot of pure oxygen through a .5 micron stone will get you to the 10 ppm level. In higher gravity worts you will need to double or even triple the time of the injection.
Home brewers can find small canisters of oxygen at the local hardware store as well as most big box DIY stores. You can also pick up a regulator with tubing and a .5 micron stone at our store.Oxynator kit
For perfect fermentations make sure you pitch plenty of healthy, vital yeast and make sure you give them plenty of oxygen to do their job. Take care of your yeast and they will take care of your beer!