When determining the size of your mash tun, there are a few factors to consider. The main consideration is the maximum grain capacity that your mash tun can hold. This is important because you want to ensure that your mash tun can accommodate the amount of grain needed for your specific recipe.
To calculate the maximum grain capacity, you can use a general guideline of 1.25 quarts of water per pound of grain. So, for example, if you plan on using 12 pounds of grain, you would need a mash tun that can hold at least 15 quarts (or 3.75 gallons) of water. This would allow enough space for the grain to mix with the water and create a proper mash.
In addition to the maximum grain capacity, you also need to consider the total strike water volume. This is the amount of water needed to initially mix with the grain to achieve the desired mash thickness. For a 12-pound grain bill, you would typically need around 3 gallons of strike water.
Therefore, a mash tun with a capacity of at least 4.87 gallons (or 19.48 quarts) would be suitable for a 12-pound grain bill, as it would allow enough space for both the grain and strike water.
However, it’s worth noting that you may want to consider a larger mash tun if you plan on brewing larger batches or using higher grain bills. For example, if you’re brewing a 5-gallon batch and want to use a grain bill of 20 pounds, you would need a mash tun with a maximum grain capacity of at least 37.2 pounds. This would require a mash tun with a capacity of around 15.097 gallons (or 60.39 quarts).
It’s always a good idea to have some extra space in your mash tun to account for any potential issues or variations in your brewing process. This will ensure that you have enough room to properly mix the grain and water and achieve the desired mash consistency.
The size of your mash tun depends on the maximum grain capacity and total strike water volume needed for your specific recipe. It’s important to consider these factors and choose a mash tun that can accommodate both the grain and water, with some extra room for variations.