In my personal experience as a brewer, I have found that using one can of fast pitch yeast in a 5-gallon batch is typically sufficient. However, there are a few factors to consider when determining the appropriate amount of yeast for your beer.
Firstly, it is important to note that fast pitch yeast is often manufactured in a concentrated form, which means that it can be diluted before pitching. Diluting the yeast can help ensure that it is evenly distributed throughout the batch and provides enough active yeast cells for fermentation.
If you choose to dilute the fast pitch yeast, a commonly recommended ratio is to dilute one can with an equal amount of water, resulting in a total volume of 2 liters. This diluted yeast solution can then be used to create a starter.
A starter is essentially a small fermentation that is created prior to pitching the yeast into the main batch. It allows the yeast to multiply and become more active, ensuring a healthy and vigorous fermentation. Creating a starter can be particularly beneficial when using a single can of fast pitch yeast, as it helps to increase the yeast cell count.
To make a 2-liter starter, you can simply mix the diluted fast pitch yeast with an appropriate amount of malt extract and water in a sanitized container. The starter should be aerated well, either by shaking the container vigorously or using an aeration device. It is also important to maintain proper fermentation temperature during this process.
Allow the starter to ferment for a couple of days, periodically shaking the container to keep the yeast in suspension. Once the starter is fully fermented, you can pitch the entire contents into your 5-gallon batch of beer.
By creating a starter, you are essentially providing the yeast with an optimal environment to multiply and become more active. This can help ensure a healthy fermentation and minimize the risk of off-flavors or stuck fermentation.
That being said, if you prefer a simpler approach, using one can of fast pitch yeast without dilution can still be effective for a 5-gallon batch. The yeast will still ferment the beer, although it may take a bit longer to reach full attenuation and may potentially produce slightly more esters during fermentation.
One can of fast pitch yeast can be sufficient for a 5-gallon batch of beer. However, diluting the yeast and creating a starter can help ensure a healthy and vigorous fermentation. Ultimately, the decision on whether to dilute the yeast and create a starter depends on your personal preference and brewing practices.