Changes

Beer or wort can be inoculated with any commercial (and homebrewed) sour /wild/funky beer that 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. 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. 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). 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.

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 defeeats 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.

If the brewer is intending to re-use the ''Lactobacillus'' or other lactic acid bacteria in the bottle, then a starter is a good idea regardless of the bottle's age. In general, a [[Lactobacillus#Starters_and_Pitching_Rate|larger population of lactic acid bacteria]] is beneficial if lactic acid production is desired. It is possible that smaller pitch rates of ''[[Pediococcus]]'' and hardier ''Lactobacillus'' strains might still sour the beer over time, but in general , making a starter will help ensure that a healthy pitching rate of bacteria is used.

After prolonged time in a bottle, microorganisms won't be at their peak vitality, and so making a starter for dregs is recommended in general. ''Saccharomyces'' strains may or may not be viable at all after an extended time in a low pH beer, but ''Brettanomyces'' and some lactic acid strains are more acid -tolerant and should be viable. Making a "step " starter is the best practice for ensuring that a high enough population of microbes are pitched. Begin by making a ~200 mL DME starter of usual strength (1.030-1.040 SG) <ref name="preiss">[https://www.facebook.com/groups/MilkTheFunk/permalink/1268830686478476/?comment_id=1269605776400967&comment_tracking=%7B%22tn%22%3A%22R%22%7D Conversation with Richard Preiss on step starters for dregs on MTF. 03/27/2016.]</ref>. Hops should not be used unless the brewer wants to try and suppress the ''Lactobacillus'' in the commercial beer (''Lactobacillus'' strains for some commercial breweries are fairly hop tolerant up to 20-25 IBU. See [[Lactobacillus#Hop_Tolerance|Lactobacillus Hop Tolerance]] for more information). If the brewer has only one bottle or wants to keep multiple bottle dregs separate from each other, the starter wort can be poured directly into each bottle and covered with plastic wrap. Alternatively, the dregs from multiple bottles can be combined into a single vessel (such as an Erlenmeyer flask or glass jug) with the starter wort, and covered with sanitized tin foil to allow an exchange of oxygen and CO2. The mouth of the bottle may be flamed with a lighter to kill any wild yeasts that might have landed on the area. The dregs don't need to be "washed" or treated in any special way before being added to the starter wort.