Pucker Up (Sour mashing vs. Kettle souring)

A guide to quick souring processes 

Kettle Souring:

Very similar to the sour mashing process, sour kettling allows you to produce a sour wort that can then be boiled for sanitation before moving it into your fermentation equipment. Overall though, souring in the boil kettle allows for greater versatility and as a process can often be more easily regulated. This method also allows you to choose whether to kill the Lactobacillus before fermentation by yeast or to allow its continued activity in your aging beer. Sour kettling begins with the use of a completely standard mashing and sparging procedure. If you want to kill Lactobacillus before the rest of your fermentation, then you will perform the steps of sour kettling before the boil. Oppositely, if you want Lactobacillus to survive into your final product, then the boil is conducted before the sour kettling procedure.


Sour Mashing:

Sour mashing is a process in which a typical mash is conducted, but is then allowed to remain warm for up to several days after an inoculation withLactobacillus. This inoculation can come from either a pure culture of Lactobacillus, a Lactobacillus starter, or from the addition of a small portion of un-mashed base grain, which will naturally have one or more wild stains ofLactobacillus on its husks. After a certain level of souring has been achieved, the mash is sparged as normal and followed by standard boiling and cool-side fermentation practices. The benefit of this method is that Lactobacillus and any other bacteria present in the mash will be killed by the boil and only sanitized beer will move forward into fermentation equipment. The downside of this process is that, of the three methods we will discuss, this one is the most difficult to control and the one most likely to yield off-flavors. The following practices will help you gain the best results from a sour mash, but as we will discuss in Part 3, are not a guarantee of success.