The impact of sulfites on making sauergut, and a few other interesting tidbits
Posted: Mon Feb 13, 2017 9:52 pm
A while back, I experimented with making some sauergut cultures a few different ways. One of the interesting phenomena that I discovered was the fact that a LoDO wort made with sulfite seemed to slow the initial growth of the LAB, compared to a LoDO wort made with ascorbic acid. Here's some data:
Both worts:
9 plato OG, cooled to ~117 F
Filled to the brim in a mason jar
pH manually dropped to 4.5 with 10 g/l acid malt
inoculated with 10 g/l pilsner malt
I incubated the sauergut in a sous vide water bath, and took pH measurements every so often over a 24 hour period:
pH measurements for the ascorbic batch:
0 hours: 4.5
3 hours: 4.0
6.5 hours: 3.8
24 hours: 3.5
pH measurements for the SMB batch:
0 hours: 4.5
2.5 hours: 4.5
3.5 hours: 4.5
5 hours: 4.5
17 hours: 3.6
24 hours: 3.5
I found it interesting that the SMB wort seemed to introduce a lag phase for the LAB, but after 24h the end result was the same. I prefer to use SMB over AA, though, because anecdotally I think it works better.
Once a mother culture is made, however, refreshing it with fresh wort from a brew seems to restart the souring process immediately (evidenced by CO2 production by the heterofermentative LAB after 1-2 hours), even when the wort contains sulfites.
A few more interesting tidbits:
Sauergut inoculated with Weyermann acidulated malt only never soured. After I tossed some pilsner malt in, it soured. Makes me think that Weyermann acid malt doesn't actually have any live bacteria on it. I'm not sure about other brands.
Pinnacle Nutrition brand probiotic pills (supposedly containing 4 different strains of lactic acid bacteria) didn't sour the wort at all in the 4 or 5 times I tried using them, even when throwing 4 pills into ~1 liter of wort (each pill supposedly contains on the order of 20 billion live cells).
WLP677 (lacto d) worked fine for me in multiple attempts, but seems to prefer an incubation temperature closer to 110 F. However, I see better results using raw pilsner malt to inoculate, and it's a lot cheaper too.
Both worts:
9 plato OG, cooled to ~117 F
Filled to the brim in a mason jar
pH manually dropped to 4.5 with 10 g/l acid malt
inoculated with 10 g/l pilsner malt
I incubated the sauergut in a sous vide water bath, and took pH measurements every so often over a 24 hour period:
pH measurements for the ascorbic batch:
0 hours: 4.5
3 hours: 4.0
6.5 hours: 3.8
24 hours: 3.5
pH measurements for the SMB batch:
0 hours: 4.5
2.5 hours: 4.5
3.5 hours: 4.5
5 hours: 4.5
17 hours: 3.6
24 hours: 3.5
I found it interesting that the SMB wort seemed to introduce a lag phase for the LAB, but after 24h the end result was the same. I prefer to use SMB over AA, though, because anecdotally I think it works better.
Once a mother culture is made, however, refreshing it with fresh wort from a brew seems to restart the souring process immediately (evidenced by CO2 production by the heterofermentative LAB after 1-2 hours), even when the wort contains sulfites.
A few more interesting tidbits:
Sauergut inoculated with Weyermann acidulated malt only never soured. After I tossed some pilsner malt in, it soured. Makes me think that Weyermann acid malt doesn't actually have any live bacteria on it. I'm not sure about other brands.
Pinnacle Nutrition brand probiotic pills (supposedly containing 4 different strains of lactic acid bacteria) didn't sour the wort at all in the 4 or 5 times I tried using them, even when throwing 4 pills into ~1 liter of wort (each pill supposedly contains on the order of 20 billion live cells).
WLP677 (lacto d) worked fine for me in multiple attempts, but seems to prefer an incubation temperature closer to 110 F. However, I see better results using raw pilsner malt to inoculate, and it's a lot cheaper too.