Tuesday, January 1, 2013

Water Kefir Soda - How Cool is that?!

A selection of sodas in second ferment
After a few days of playing with converting dairy kefir grains, designed to feed on milk and create a high probiotic beverage, kefir, into something that would feed on sugar, I decided to get the real thing: water kefir grains. Sadly, my converted dairy kefir grains did die, and I knew there was a high chance of that happening. On the flip side, the water kefir grains are another side of fascinating.

Water Kefir Grains are yet another symbiotic community of bacteria and yeast (SCOBY) that ferment cane (or palm) sugar. They are a complex, not completely understood, SCOBY that appear to be translucent plastic shipping filler, or something like that. Their origins aren't as clear as that of dairy kefir, which are indisputably from the Caucus mountains. It does seem that they originated in Mexico, but have traveled the world afar, and that they are different from a similar looking and acting SCOBY called ginger beer plant.

More importantly, they are awesome to experiment with. You use the water kefir grains to create mildly fizzy, highly nutritious,  beverages through a one or two stage fermenting process. They are one type of natural soda, or sweet fizzy beverage. And the options are absolutely endless for flavoring. If you follow some basic guidelines, they will grow rapidly... so rapidly that you'll be storing them long term within a week or two.

As with dairy kefir, I am not an expert, but i've been reading a ton. Here's the single best site I've found on the Internet in terms of information and presentation: Yemoos Water Kefir Site

Yemoos has an outstanding FAQ on the left navigation bar, and they also have a photo-full how to on their website. So, I'll just talk here about our experiences and lessons learnt. I have continued to add the details of our experiments to a Google doc, including the ingredients we used, the fermentation time, and the outcome. You can find that here.

Water kefir grains

The Basics
There are a few ways to make natural soda from water kefir grains. We are using the two-step process.
  • First, you ferment your grains in sugar water with some dried fruit. If your water is not hard and full of minerals, you also want to add some other growth supporting ingredients, like a slice of lemon and baking soda.  You can also add ginger here. The key here is to ensure that you have no chlorine in your water. If you have city water, you must let the chlorine evaporate, and you should add the other ingredients. This is about 6 cup H2O, 1/2 cup sugar, 1/2-1 cup grains, 1 tsp. molasses, 1 slice lemon, 1/8 tsp. baking soda. All put into a jar, sealed or not.
  • Second, we strain the grains after 48 hours and start them in sugar water. They will have grown. Even in our cold house (62-68degF), we are seeing growth of nearly 100% every 48hours. 
  • Then, take the water kefir that you have created in the first step into your soda by mixing it with some new sugar source, or leaving it as it is, bottling it, and letting it sit out and ferment another 24-48 hours.  Then refrigerate. In this second step all of your creativity comes in. You can mix 25-50% fruit juice into the kefir, add other fruits, add spices or herbs, extracts...  
A word of caution: In the second ferment, you have a high risk of over-carbonation and  your container exploding if you aren't careful. The kefir is full of yeasts that feed on the new sugar you've added, creating CO2 and alcohol. Bottling that to get the fizz of soda also pressurized the bottle. If you let it sit out too long, it will eventually explode. Figuring out how long is long enough is part of the experiment, it will depend on your kefir, how much new sugar you've added, the container, the temperature of the room, and probably other things. Experiment by using 24 hours as a baseline.

Our experiments

We've only had our water kefir a few weeks -- and we have plenty to share, so if you want to try some out, just let me know! I have been measuring the growth of the grains. It varies, but we've easily seen it double in 48 hours. We are now preparing to start saving some off, both by drying them and sugar packing them into the freezer.

First Ferments. In our first ferments, we aren't veering too far from the basic recipe, since the SCOBY needs to be kept alive. We have tried various cane sugars: white, brown, turbinado, sucanat. We have added and not added molasses. For the dried fruit in the first ferment, we've added figs, raisins, cranberries, apricots, prunes.  We have done a batch with about 0.5oz of ginger -- wow, that was gingery!

Ingredients... The ingredients molasses, egg shell, baking soda, and lemon are all used to support the growth of the kefir and increase mineral content. We have done batches with and without all of them. We haven't used lemon slices yet, as we don't have fresh lemons about, and instead used a bit of lemon juice. Some websites swear you must use some molasses or unrefined sugar, others say that in the winter, the grains do better with fully refined sugar. Mix it up.

Besides playing with the dried fruit, the traditional ingredients, and the addition of something like ginger, don't mess too much with the first ferment -- well, don't use your only grains to do that. Experiment in the first ferment with extra grains, which are easy to come by with water kefir!  

Growth and progress... The first ferments definitely seem to vary in how quickly they ferment and how much they grow, but I can't say exactly why. We have had one mix seem to get "stuck" and after 48 hours it was still somewhat sweet. With this batch, I through the water away, washed the grains and started again. The grains perked right back up. I had used cranberries - and only cranberries - in that mix. Cranberries usually have some oil on them, so it could have been that, and it could also have been that I used only one dried fruit. Not sure.

In our first ferment we are using 1 cup of grains and, for the most part,  the grains are doubling in quantity every 48 hours. We are putting the extra grains in a sugar solution in the fridge, putting them in compost, drying, freezing, or sharing them.

Temperature and time lessons.... Our house around this time of the year runs from 62 deg F to 68 deg F, with the kitchen reaching 70 deg F during a lot of cooking.  The best way to check your first ferment progress is to watch for bubbles and taste it. You can remove the grains when the taste suits you. Just remember that if you let it ferment too long, you could allow vinegar to move in. Too little and it will be sweet and not too carbonated. As long as you "burp" the first ferment occasionally, you won't have problems with carbon dioxide build up and explosions.

What else? For our first ferment, we are using 2 qt Le Parfait flip top glass jars, the old fashioned canning jars. We bought 3 jars on Ebay from Overstock.com for a very reasonable price and free shipping. The 2 qt is the best size, I think. It makes 3-4 bottles of soda every few days and you don't have to adjust the recipe for the kefir.

Flavourings in the Second Ferment. We are transferring the water kefir from the first ferment into standard flip top beer bottles and adding our flavorings. For each batch of water kefir we make, we get 3-4 bottles of natural soda, depending on what flavorings we choose. We are generally allowing the second ferment 24 hours, but we have tried a range of 20-36 hours. All of these choices effect the taste and texture of your final soda.

In the second ferment, we have combined a number of juices with the kefir, as well as jam and different kinds of sugars. We have done:
  • apple, pomegranate, orange and cherry juice mixes from 25-50% of the solution. We have pineapple, grape, and a few others in waiting. 
  • black raspberry and peach jam at 2Tbsp per 16oz kefir (in Grolsch 16.9oz bottles)
  • vanilla extract
  • Lemon juice (2Tbsp) with 1tsp - 1 Tbsp of sugar (we preferred 1tsp),
  • other sugars: honey and maple at 2Tbsp per 16oz kefir
  • cinnamon stick and cloves
  • fresh ginger
You can also add fresh or frozen fruit, but you also have to get it back out of your bottle. :) Puree works pretty well.

How much sweetener?  How much juice or sweetener to add, combined with how long you ferment, will greatly effect your final drink. I like my drink not very sweet and having a lot of champagne like bubbles. For that, I've found a ratio of 4:1 kefir to juice to work well, with 24 hours of fermentation before refrigeration. If I'm adding sweeteners like sugar, honey, and maple, we first tried 2Tbsp per bottle, but that is too sweet and not bubbly enough for my taste -- instead about 1 tsp seems to do the trick. We've also fermented just the kefir alone. Leaving this closer to 36 hours gives a bubbly, somewhat sour beverage.

We have a running spreadsheet on Google docs that you can review, which lists all of the combinations we've made and what we thought of them. It is found here:

Water Kefir Experiments

Carbonation. I've done a lot of reading on carbonation, looking for the one true easy answer. It's not there. The process seems to have too many variables. It seems safe to do the second ferment in an air tight container for 24 hours. We've done 29 hours with a 50/50 juice solution, and this caused quite the "head" on the soda. I would recommend opening jars facing outward, and even outside, until you know how they'll react.
  • 20 hours in our cooler house, even with 50% juice, wasn't quite fizzy enough. The fizz is small concentrated bubbles like champagne, not big bubbles like common soda. 
  • 29 hours with 50% pomegranate juice in a soda bottle filled probably too full (leaving about 2" headspace) had a ton of carbonation and it didn't die over 24 hours after opening. 
  • We started by filling the jars up past the narrowing of the neck of our Grolsch-style bottles and, mixed with juice, had lots of fizz. We backed down to the base of the neck, and at 24 hours, the fizz is quite mild. I think you have to play with how full they are and how long to leave them, as well as, of course, how much sugar you feed them. 
  • All the mixes that we did with just kefir and sugar/spice, no juice, had only mild effervescence.
I feel like we haven't got this down well enough, so we'll keep playing with the main variables.

Containers. For our first ferment, we are using Le Parfait flip top jars, 2 Litres in size. You can use any 1-2 qt. jar.  Whether you seal it or not, or burp it, during the first ferment will change things slightly, but I don't think significantly. For our second ferment, we are using Grolsch-style flip top bottles for our soda that we purchased at Maryland Homebrew in Columbia, MD. They are about $33 for 12 bottles. We also tried second ferments in plastic bottles. Milk comes in type 2 plastic, and it is safer than soda/juice bottles that are type 1. The plastic bottles will push out so you can feel the carbonation. having said that, so far, we haven't been impressed with the fizz of those made in plastic.  We tried the second ferment in mason jars, again with mixed success. We had fizz, but not the full fizz we got from the flip top bottles.