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Many brewers, however, do not aerate their wort when either pre-souring the wort with a pure culture of lactic acid bacteria, pitching fresh wort on top of a mixed culture yeast cake, co-pitching a mixed culture such as Wyeast Roeselare, or pitching a custom mix of microbes from multiple sources <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1182597671768445/?qa_ref=qd Conversation on MTF about oxygenating wort for mixed culture fermentation. 11/22/2015.]</ref>. Many such brewers have reported success without aerating. We therefore recommend that the brewer investigate and experiment with their process in order to decide whether or not aeration is desired.
If the brewer is pitching a separate liquid culture of ''[[Saccharomyces]]'', it is recommended to create a starter on a stir plate and alternatively dose it with oxygen. This will allow the cell membranes to build enough lipids for their cells walls and give them the greatest chance of fermenting the wort without off-flavors <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1284106178284260/?comment_id=1284141108280767&comment_tracking=%7B%22tn%22%3A%22R3%22%7DConversation with Mark Trent on MTF regarding aerating starters/wort for mixed culture fermentations. 04/13/2016.]</ref>. If the wort has been pre-soured, it might be beneficial to propogate the yeast starter with a portion of the soured wort equal to the portion of starter wort in order to acclimate the yeast to the has conditions (see [[Saccharomyces#Fermentation_Under_Low_pH_Conditions|''Saccharomyces'' fermentation under low pH conditions]]). Dried yeast is grown and processed in such a way that they contain enough lipids to support a healthy fermentation of 5% ABV or less without the need for aeration (this may be dependent on manufacturer; see the yeast manufacturer's website for their individual recommendations). Aeration should be considered for beers above 5% <ref name="danstar"></ref>. Mixed cultures can also benefit from a starter if they are expired or haven't been stored correctly (see [Mixed_Cultures#Starters_and_Other_Manufacturer_Tips|mixed culture starters]).
===Microbe Inoculation===