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===Creating a Starter===
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 ~200 100 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.
Although more experiments are probably needed, agitation is believed to be an important factor for any species of microbe (yeast and bacteria). Gentle stirring on a stir plate or orbital shaker, or frequent gentle manual agitation leads to faster growth and a higher number of organisms. Agitation keeps the microbes in solution. It also maximizes the microbes' access to nutrients and disperses waste evenly. In a non-agitated starter, the microbes are limited to the diffusion rate of nutrients, leading to a slower and more stressful growth <ref name="BryanHeit_starters">[https://www.facebook.com/groups/MilkTheFunk/permalink/1168024059892473/?comment_id=1174865305875015&reply_comment_id=1176092372418975&total_comments=1&comment_tracking=%7B%22tn%22%3A%22R9%22%7D Conversation with Bryan of Sui Generis Blog about starters and agitation. 11/09/2015.]</ref>. Allowing for at least some oxygen to enter the vessel will help ''Brettanomyces'' grow, and limiting oxygen will help any surviving ''Saccharomyces'' to grow. For more information regarding aeration and agitation effects on ''Brettanomyces'' growth, see [[Brettanomyces_Propagation_Experiment|Mark Trent's Brettanomyces Propagation Experiment]] and [[Mixed_Cultures#Effects_of_Mixed_Cultures_on_Growth|Effects of Mixed Cultures on Growth]].