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Any commercial (and homebrewed) sour/wild/funky beer can be used to inoculate another beer and/or wort as long as it is not kettle soured or pasteurized. Dregs can be used from many types of sour/wild/mixed fermented commercial beers (as long as they are not kettle sours or pasteurized), including [[Mixed_Fermentation|mixed fermentation]] sour beers where the microbes that the brewery used are from a yeast lab, wild-fermented beers that use [[Wild_Yeast_Isolation|wild-caught or bioprospected microorganisms]], Belgian [[lambic]] and non-lambic sour beers that are [[Spontaneous_Fermentation|spontaneously fermented]] in a coolship, beers that are co-fermented with [[Brettanomyces_and_Saccharomyces_Co-fermentation|''Saccharomyces'' and ''Brettanomyces'']], etc. The instructions on this wiki page apply to all of these types of beers (in other words, spontaneously fermented beers don't need to be treated differently than mixed fermentation beers using lab yeast/bacteria).  Generally, only the last half inch of a bottle's contents, including the sediment, is used. This portion of the beer is often referred to as "the bottle dregs". It is recommended that the microbes in the beer are first reinvigorated with a small starter wort of around 1.030 gravity before it is added to the fermentation vessel. A fresh pitch of regular brewers yeast is often advised to use along with the dregs, but this is not always a requirement if the commercial beer still has viable ''Saccharomyces'' yeast in it. Using commercial sour beers to ferment is generally a good idea because the microbes are often stronger and more aggressive from commercial breweries as compared to mixed cultures from yeast companies (this is a generalization; smaller and more specialized yeast labs offer very aggressive alternative yeast and bacteria strains). It is generally advised to use as fresh of a bottle of commercial sour beer as possible, however, older bottles can be used as well depending on the brewery, the microbes in the beer, and how the bottle was stored.

The following information is specific to collecting microbes from commercial bottles of mixed fermentation sour beers or ''Brettanomyces'' beers. For instructions on collecting ''S. cerevisiae'' from clean beersthat only contain this species of yeast and no other microbes, check out [https://www.jaysbrewing.com/2012/09/05/9-steps-to-culture-yeast-from-a-bottle/ this guide].

An often asked question in the Milk The Funk Facebook group is whether or not dregs should be added to a [[Wort_Souring#Souring_in_the_Boiler_.28Kettle_Sour.29|kettle sour]]. While there is no reason why it wouldn't produce a good beer (assuming the dregs are in good health), it defeats the purpose of making a kettle -soured beer. The primary advantage to kettle souring is the ability to make a sour beer without risking exposing the brewer's cold side equipment to potential brewery contaminants such as ''Brettanomyces'' and lactic acid bacteria.