Acid Lake
Swimming not advised. Spores welcome.
Tour the set
Press the numbers and see what’s what.

Your guide to Acid Lake
The stomach is a stretchy muscular bag that churns food with acid and enzymes into a thick soup called chyme. Its lining makes hydrochloric acid, enough to bring the lake down to about pH 1.5 to 3.5.
The acid unfolds proteins and switches on pepsin, the stomach’s own protease. A thick layer of mucus keeps the lake from digesting its own shoreline. Most microbes don’t enjoy the swim, which is why Sporty (B. coagulans) travels packed in a spore.
Stomach acid runs at about pH 1.5 to 3.5. It starts protein digestion with pepsin, and spores like Sporty ride straight through it.
Each step on the pH scale is ten times more acidic, so pH 2 is about 100,000 times more acidic than pure water.
Locals and staff
Very few microbes settle here. Sporty passes through in his spore coat and hatches downstream.
Passport stamp
Your passport so far
Passport · Channel GG
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Next stop down the gut · Stop 4
Bubble Works
The liver and gallbladder. Bile is made in the liver and stored in the gallbladder. It’s a soap, not an enzyme.


