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[https://eurekabrewing.wordpress.com/2015/05/18/evaluate-starter-media-to-propagate-lactobacillus-sp/ Samuel Aeschlimann from Eureka Brewing Blog] ran a set of experiments that found a DME based recipe for starter wort that produces a very high cell density similar to that of MRS media, which provides optimal growth rates for ''Lactobacillus''.
The recipe for this starter wort is: '''1.040 SG (10°P) Dried Malt Extract wort with 10% apple juice + 1.5-2 grams of chalk (CaCO3) per liter + yeast nutrients''' (originally, Aeschlimann recommend 20 grams of chalk, but we now recommend a much smaller amount of chalk; see below for details). This starter wort might be as effective without the 10% apple juice addition, but this has not been tested as far as we know. Regarding the use of chalk, it is the preferred buffer because it does not react is relatively nonreactive with CO2 (unlike CO<sub>2</sub> compared to something like baking soda), so it won't be consumed by exposure to air due to CO2 production by the Lacto. It also has a pKa (maximum buffering capacity) of around 4.6, which is ideal for ''Lactobacillus'' growth. The fact that it easily precipitates out also makes it ideal to use as a buffer <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1180630378631841/?comment_id=1181674265194119&reply_comment_id=1181743348520544&comment_tracking=%7B%22tn%22%3A%22R%22%7D Conversation with Bryan of Sui Generis Blog regarding the use of chalk as a buffer in Lacto starters. 11/20/2015.]</ref>. Jeff Mello from [[Bootleg Biology]], Nick Impellitteri from [[The Yeast Bay]], and Bryan from [https://suigenerisbrewing.blogspot.com/ Sui Generis blog] suggest that using the smaller amount of 1.5-2 grams of CaCO3 per liter is preferable because that amount is easier to precipitate out of the starter and avoid pitching into the beer (the growth differences from using less chalk has not been tested though) <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1369904163037794/?comment_id=1370329352995275&reply_comment_id=1372184639476413&comment_tracking=%7B%22tn%22%3A%22R%22%7D Conversation with Jeff Mello on MTF regarding using less chalk in LAB starters. 08/10/2016.]</ref><ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1619935741367967/?comment_id=1619986154696259&reply_comment_id=1619991214695753&comment_tracking=%7B%22tn%22%3A%22R9%22%7D Impellitteri, Nick. Milk The Funk Facebook group. 03/19/2017.]</ref><ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1457469187614624/?comment_id=1457541770940699&reply_comment_id=1457620514266158&comment_tracking=%7B%22tn%22%3A%22R%22%7D Bryan from Sui Generis. MTF Thread on using 1.5g/L of chalk for Lactobacillus starters. 11/02/2016.]</ref>. To create a 1 liter starter for 20 liters of wort, follow these directions:
# Add 100 grams of DME to around 900 mL of water and heat pasteurize/boil as you would normally do for a starter. This should make 1.040 SG (10°P) starter wort.