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Gose "Advanced Stream" video - some questions

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Hi Really enjoyed Josh's video last night about gose beers. I tried to post some questions but the program would not allow me to... So perhaps I can ask the questions here.

1. Josh said that simply adding lactic bacteria (LAB) would take months for the beer to sour. I have been experimenting with "rejuvelac" - a drink made by adding water to sprouting grains (say wheat berry or quinoa or rye) and after three days the pH of the water drops to about 3.7 because of the LAB that has been encouraged to grow. Why would it take so much longer for LAB to work in a wort?

2. The video showed Josh adding lactic acid rather than LAB but immediately adding yeast. But what would happen if he had added LAB? Would the yeast swiftly take over and inhibit or prevent the LAB from acidifying the wort? What would the LAB convert to lactic acid if the yeast ferment all available sugar? Is there sugar that the LAB can get at that yeast cannot?

3. And this may be a laughable question - but if I add LAB to a wort can I still use lactose to add more sweetness (the yeast cannot ferment lactose) or will the LAB simply use any added lactose to make the wort even more sour?

Thanks

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4 hours ago, Brewer said:

Hi Really enjoyed Josh's video last night about gose beers. I tried to post some questions but the program would not allow me to... So perhaps I can ask the questions here.

1. Josh said that simply adding lactic bacteria (LAB) would take months for the beer to sour. I have been experimenting with "rejuvelac" - a drink made by adding water to sprouting grains (say wheat berry or quinoa or rye) and after three days the pH of the water drops to about 3.7 because of the LAB that has been encouraged to grow. Why would it take so much longer for LAB to work in a wort?

2. The video showed Josh adding lactic acid rather than LAB but immediately adding yeast. But what would happen if he had added LAB? Would the yeast swiftly take over and inhibit or prevent the LAB from acidifying the wort? What would the LAB convert to lactic acid if the yeast ferment all available sugar? Is there sugar that the LAB can get at that yeast cannot?

3. And this may be a laughable question - but if I add LAB to a wort can I still use lactose to add more sweetness (the yeast cannot ferment lactose) or will the LAB simply use any added lactose to make the wort even more sour?

Thanks

 

1. Kettle souring is quicker, but I didn't want to get too much into detail on that subject yet (I will do a video about it soon). The reason it takes longer in a wort is because of the presence of hops. Hops are antibacterial, LAB is a bacteria, therefore, hops will inhibit its process. Some species of LAB are more hop tolerant than others, but they are all still inhibited by the alpha acids in hops. During the aging process, the hops die out and the LAB starts working more. Some brewers are now using aged hops in their sour beers instead of fresh (more on this later). Anyway, this is why kettle souring is always done before the boil. Once it's soured, then they will do the boil, which will also kill off the leftover bacteria. Kettle souring is the fastest way to do it and I will do a show on that soon, but in the meantime, Milk The Funk is the best resource for information on souring your beers. http://www.milkthefunk.com/wiki/Main_Page

 

2. You will actually add the lactic acid 1 week before bottling and not before the yeast (I may have forgot to mention that in the video). With that said, you can add LAB and yeast together. In fact, you can even buy blends of LAB, Sacc, and Brett (Sour Batch Kidz from Imperial yeast is my favorite blend). The yeast and bacteria do not compete for sugars. The LAB will depend more on carbohydrates in this environment. They will ferment some sugars, but usually just the ones the yeast can't. In fact, they have more of a symbiotic relationship than a competitive one. LAB will also consume some byproducts of the yeast, as will the wild yeast strain, Brettanomyces. 

 

3. Definitely not a laughable question. Yes, you can add lactose with LAB and, no, it will not consume the lactose. This is actually becoming a new trend among some brewers with their "sour milkshake IPAs" and such. A good friend of mine made a NE IPA style beer that he soured and added lactose to. With the fruity Galaxy hops, the moderate acidity, and subtle sweetness, it tasted just like pineapple juice. It was so good! Lactose won't change the pH of the beer, but it will lessen your palate's perception of sour slightly.

 

LAB is not a good fermenter on its own unless it's coaxed with heat in an anaerobic environment with 0 hops present (kettle souring). It must be paired with a yeast to get the full benefits. As you can see from this wiki article from MTF, 100% LAB fermentations are pretty much impossible. http://www.milkthefunk.com/wiki/Lactobacillus#100.25_Lactobacillus_Fermentation

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