13,700
edits
Changes
m
no edit summary
====Malt Inoculated Wort====
In 2016 and 2017, Dr . Matt Bochman or Indiana University and Jeff Young of [http://blueowlbrewing.com/ Blue Owl Brewing] conducted an experiment to map the microbiome of wort that was inoculated with several harvest years and harvests varieties of malted barley. Using DNA sequencing, they analysed analyzed the microbes present in 110°F wort that was inoculated with crushed malted barley at 0 hours, 24 hours, and 48 hours. The 7 malted grains that used to inoculate the wort were:
* 2015 Breiss Merit 57
* 2016 Weyermann Barke
The grain samples before inoculation hosted a large variety of microbes, but immediately after inoculating the malted grains into 110°F wort, all of the grain samples were dominated by ''Weissela cibaria'' (ranging from 92-99% across all samples), a Gram-positive bacteria that is in the same order but a different family as ''Lactobacillus''. All but one of the grain samples also had a much smaller but not insignificant population of ''Salmonella bongori'' (1-4% across all samples), which has been associated with non-lethal food poisoning <ref>[https://en.wikipedia.org/wiki/Salmonella_bongori#Pathogenicity_and_epidemiology "Salmonella_bongori". Wikipedia. Retrieved 06/15/2017.]</ref>. There were also trace populations of other bacteria such as ''Enterobacter'' spp., ''Pantoea'' spp., ''Erwinia'' spp., and ''Lactococcus lactis'' in most of the samples. There was a significant ''L. lactics'' population in the 2016 Weyermann Barke, as well as ''Enterobacter aerogenes'' <ref name="blueowl_2017">[https://experiment.com/projects/mapping-the-sour-beer-microbiome/results "Mapping the sour beer microbiome". Matthew Bochman and Jeff Young. Experiment.com. 2017. Retrieved 06/15/2017.]</ref>.
After 24 hours of continued 110°F inoculation in the wort, all but 2 samples were almost completely dominated by ''Weisella cibaria'' (98-99% across all samples). The 2016 Weyermann Barke also had a small population of ''Lactococcus lactis'' (5%). The 2016 Breiss Merit 57 was significantly different than the other grain samples, and was the only sample with a very large population of several species of ''Lactobacillus'' (38% ''Lactobacillus reuteri'', 23% ''Weissla cibaria'', 15% ''Lactobacillus delbruekii'', 12% ''Pedioccocus pentosaceus'', 8% ''Lactobacillus fermentum'', and 3% ''Lactobacillus helveticus''). This data indicates that ''Lactobacillus'' is generally not the dominant organism when inoculating with grain samples at this temperature, despite popular belief. It was the thought of the authors that ''Lactobacillus'' species might dominate at lower or higher temperatures, but more studies are needed to show this. In addition, only a very small population is required to begin with on samples that do, and once inoculated into wort at 110°F, their population will increase significantly <ref name="blueowl_2017" />.