Saturday, January 14, 2006

Ginger soda - mixed results

This week I decided it was time to try the ginger soda I had started in December. Some mixed results that I don't fully understand, so I'm going to go in to a lot of detail here.

A friend had made a good batch of ginger soda & given me a bottle. After drinking most of it, I saved the sediment at the bottom in my fridge, for some months.

When I was ready, I mixed 1/2 of the sediment with water, grated ginger, and white sugar. (I wonder if the mineral content of rapdura would work better. Yeast needs nutrients.)

I keep my house pretty cool in the winter, at least by US standards -- 62deg F (17deg C). I've noticed that at this temperature many of my cultured foods go pretty slowly. To help the culture along, I put the jar in the oven with just the light on. Recently I measured with a thermometer, and it's probably about 80deg F in there.

Every day I added more ginger & sugar to feed the culture. As it grew, I split in to two jars to keep one in reserve.

Finally the big day came. I boiled 1.5gal filtered water w/ a stick of fresh ginger, grated. Then added sugar (don't remember how much, but it was sickly-sweet). Let it cool, which took a while.

First vessel was a 1gal apple cider jar. Poured in 2qts of the mix, through a plastic funnel. Added filtered water to 1/2in from the top. Put a latex balloon over the mouth to measure CO2 production and restrict oxygen exposure. There are special devices for this, but I didn't have one.

Then I juiced a few fresh, organic lemons and added to the mix (but not in the first vessel). A friend is allergic to citrus, and he loves ginger soda, so this one was for him.

Second vessel was another 1gal apple cider jar. Again, 2qts of mix, add water. Another balloon.

Third vessel was a 1.5L Grolsch bottle, with swing-top (aka bail-top) lid. This is the only one that isn't clear.

Forth vessel was a 1/2gal jar that Kevin bought me at IKEA. A thoughtful gift from a friend. It has a wide mouth with a swing top.

3 of the vessels have narrow mouths, so they're hard to clean. It's possible that the insides weren't spotless. I am sure I had rinsed them out very well, so I don't think there was much soap or anything, but maybe some dried-on stubborn matter was still there. They looked clean to the eye. I now own 2 bottle brushes that should work well in these containers, and an in-sink bottle washer.

The vessels went in to the guest room where they wouldn't be disturbed. (Why do I own an entire room that is only used for 2-4 weeks per year? Topic for another blog.) Every day or two I checked on them, and vented the balloons if they were full. Here's how it went.

Vessel #1 (no lemon) never produced a single bubble. After a full month, the balloon had been sucked in slightly. A bit of mould grew on the surface. Dumped down the drain.

Vessel #2 started bubbling very soon. It made the balloon stand erect 3-4 times. Then it went quiet. At one point I tried moving it to a warmer part of the house, but it never produced more gas.

Vessel #3 (Grolsch) showed no signs of fermentation for at least 2 weeks. Then it started to bubble, and was active for the last ~3 weeks.

Vessel #4 (jar) followed the same pattern as #3.

This week I opened #3 and tasted it. It was excellent, so I decided it was time to check the others.

#4 was also good. Moved it to smaller bottles & gave them to friends.

#2 was still way too sweet. Why would the culture go inactive, when there was still so much sugar available? I added a little bit of #3 to provide a healthy, active culture. Put the jar in the oven with the light on. It became somewhat active again, but not as much as I would have hoped. It's still sweeter than I'd like, but perhaps people who drink soda every day will enjoy it. (My taste for sugar is much more sensitive these days).

So, why these variable results? Why did #2 go dormant? Why did #1 never get going? Any ideas?


Kevin said...

Did you add any other source of acid, like vinegar to the one with no lemon?

Maybe the one with no lemon became too alkaline?

Jay Bazuzi said...

Possible... I've read that yeast likes an acid medium. Distilled vinegar is made from corn, right?

Anonymous said...

I'm an experienced home brewer, mostly of beer. You're doing the same thing, with some variation in ingredients.

There are lots of things that would have contributed to your results. I'd recommend finding a local homebrew supplier, and reading whatever beginning brewing book they recommend. They will also be able to supply you with the proper equipment, chemicals, ingredients and information you'll need.

You'll want to focus first on getting more consistent results. (Once you're consistent, you can adjust your recipe for taste.) The key to consistent results is consistent process. And the key to consistent process is to eliminate as much variability between batches as you can.

For starters, I'd recommend you improve your sanitation. Brushes are a good start, but you should also find out about, and use, sanitizing solutions. If your sanitation isn't effective, you'll never get consistent results. This is especially important for you because of all of the other food fermentation you're doing -- you have more (and more vibrant) cultures floating around your kitchen than most of us.

Also, I'd recommend you adopt one consistent fermentation vessel size for all batches, to eliminate variability around batch size. Gallon jugs are a good start. And further down that road, I suggest you measure your ingredients and keep records. Weight measures are more consistent than volume, but when you're dealing with hygroscopic ingredients like sugar, it's most accurate to measure the specific gravity of the brewing liquid. The tool for that is inexpensive, and lasts forever with proper care. Having the detailed recipe written down is invaluable when you want to reproduce a batch you liked.

Your brewing temperature might have affected the outcome, but that would depend on what kind of yeast you used. Some yeasts prefer temps in the low '60's F, and some like it warmer or colder than that. Most yeasts will generate more fermentation activity at higher temps, but generate off-flavors in the process. (Back in the day, we'd culture the yeast from Red Hook's ESB, but it would add an acrid banana taste when fermented too warm.)

By using an unknown yeast cultured from someone else's bottle, you're adding the variability of not knowing what conditions your yeast will like -- you know they're the yeast cells that survived conditions in that bottle, but you don't know what those conditions were. I recommend starting with a brewing yeast culture from the homebrew store. That would give you a known starting point with respect to preferred temps, pH and so forth.

Jay Bazuzi said...

Wow, awesome! This is a lot of good information.

I'm trying to do "wild fermentation" ( which means that inconsitency is expected, but I think that I had too much!

I see that a I should cultivate my wild starter culture in an environment & medium that's similar to the final mix, so that it will do well in that context.

I remember a hydrometer from my youth. We lived in Saudi Arabia, where alochol is illegal. So, my parents brewed our own. I was just 6 years old, with 30 gallons of beer brewing in my bedroom. :-)

Thanks again!

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