All, I'd appreciate feedback on this. I'm an experienced home brewer. Long story short: I made an active ginger bug and added it to a ginger beer concoction, and 4 days later, the ginger beer shows no sign of fermenting. Details below.
I made my first ever ginger bug, fed it daily for 4-5 days, and it was moderately active, i.e., not completely foamed over, but with noticeable bubbles.
I made a 1/2 gallon wort of ginger beer by simmering ginger with demerara sugar, then after 1/2 hour added lemon juice and peel. I used the proportions in Artisan Drinks (Lindy Wilmoth).
I cooled the wort to 98 degrees, and pitched 1/2 cup of the active, strained ginger bug into the ginger beer mixture, and shook in a jug gently for 5 minutes (per homebrewing technique to distribute yeast), and put an airlock on the jug.
I have stirred it twice daily for 4 days, and there is no sign of any fermentation. There is certainly some some of cloudy trub at the bottom of the jug, but no bubbling activity. I placed the bug in the fridge and will re-activate it and pitch more bug and sugar into the wort to try to get it to activate. I'm not sure how much more time I should give it.
Please let me know why an active ginger bug, pitched into wort at a survivable temperature, would not ferment my ginger beer. Notes of possible errors:
1. Did not use filtered water, but the ginger bug didn't seem to mind. I cooled the wort by adding 1/4 gallon room temp water to it. Our water has no perceptible chlorine taste, but that might be a factor.
2. The pitch temp was 98. I read that this was within a survivable range.
3. Fermentation (room) temp is probably 55-65 degrees (I live near San Francisco). Too cold? It is stored in a dark place.
4. Demerara sugar should work, and the wort is plenty sweet. I used plain brown sugar for the bug.
5. Was 1/2 gallon too much liquid for 1/2 cup ginger bug? I read multiple times that you use 1/4 cup per quart.
6. Shaking not good for lactobacillus?
7. Let ginger bug ferment longer? I read somewhere that you want the early yeast to die off to make way for another yeast.
8. Airlock prevents helpful yeast from entering wort? I used the airlock because my first ginger beer attempt using cake yeast had a terrible gassy off flavor. I speculated that it had become infected while exposed to the open air.