{"id":551,"date":"2015-05-18T18:27:00","date_gmt":"2015-05-18T18:27:00","guid":{"rendered":"http:\/\/suigenerisbrewing.com\/index.php\/2015\/05\/18\/lacto-starters\/"},"modified":"2017-09-15T18:02:03","modified_gmt":"2017-09-15T18:02:03","slug":"lacto-starters","status":"publish","type":"post","link":"https:\/\/suigenerisbrewing.com\/index.php\/2015\/05\/18\/lacto-starters\/","title":{"rendered":"Lacto Starters"},"content":{"rendered":"\n\n\n\n
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Starter wort, for the L. brevis<\/i> and L.
\nbuchneri<\/i> to be used in my upcoming beer<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Its almost time to brew a quick sour for the upcoming summer…which means that it is time to begin preparing starters of the lacto, sacch and brett going into the beer. Its been a few years <\/a>since I blogged about brewing this kind of beer – a sour Berliner Weisse which can be ready in as little as 10 days – or which can act as the basis of more complex beers through the addition of Brettanomyces<\/i>, fruit, herbs and blending with other beers.<\/p>\n

But more on that later. Today’s post is on a topic I get asked about with some regularity; namely, how to prepare a starter for Lactobacillus<\/i>. A proper starter is especially important for sour worting, both to minimize the risk of infection by other bacteria, and also to ensure a reasonable souring time (a few days).<\/p>\n

The good news is that lacto starters are easy – almost as easy as yeast, but you do need a bit more equipment.<\/p>\n

For the starter you will need:<\/p>\n

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  1. 1.040 starter wort (or apple juice, or MRS media)<\/li>\n
  2. Yeast nutrient (optional, but a good idea, especially if using apple juice)<\/li>\n
  3. A temperature controller<\/li>\n
  4. A heat source (I use a crock-pot)<\/li>\n<\/ol>\n

    As always, details are below the fold.<\/p>\n

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    Preparing the Media<\/h3>\n

    The first step, as with growing any brewery organism, is to create a starter medium compatible with the lactobacillus<\/i>. Unhopped wort makes an excellent\u00a0 medium, as does preservative-free apple juice – but if using apple juice you must add yeast nutrient to ensure sufficient nitrogen to support Lactobacillus <\/i>growth. I personally prefer wort as I can dump the whole starter into a beer; Lacto<\/i> doesn’t always sediment nicely during a cold-crash, so pitching the whole starter is often the best option.<\/p>\n

    However, both of these media share a disadvantage – lacto<\/i> growth is limited as the bacteria will readily acidify the starter, to the point where they inhibit their own growth. Moreover, depending on the strain of lacto, they may have a limited ability to eat the more complex sugars found in wort.<\/p>\n

    If maximum lacto <\/i>numbers are critical, MRS broth (a commercial microbiology medium) is your best bet. MRS is buffered such that this pH drop is minimal, and contains glucose as an energy source. My very minimal work with MRS has shown that I average 2-5 times more Lactobacillus<\/i> when using MRS compared to an equal volume of wort. That said, the cost of MRS is easily 25x the cost of wort; sufficiently high enough that\u00a0 typically don’t bother using it.<\/p>\n

    EDIT:<\/b> in a somewhat serendipitous event, Sam of Eureka Brewing<\/a> just put up a post<\/a> comparing MRS to DME, apple juice and various other media options.<\/p>\n

    Lactobacillus <\/i>does not require oxygen, so no stir-bar is necessary. It also doesn’t care if oxygen is present, so herculean efforts to reduce oxygenation are equally unnecessary. I typically do 250-500 ml starters, and find that mason jars work well (see image at the top of this post) – I prepare the wort right in the jars, essentially canning it. If using mason jars, just remember to loosen the cap during fermentation – the gasses produced by heterofermentative strains can easily lead to a blow-out if you don’t! The volume of starter required is not well established, and will vary greatly depending on what you are trying to achieve:<\/p>\n