#2 Agar plates (Water kefir, Lactobacillus)

Eureka, this is the second post in the pentade about some agar plates. The first post was about different dregs from commercial sour beers. This post is about a water kefir culture and a Lactobacillus starter. I made a Lactobacillus starter with sterile apple juice and dumped some acidified malt in there for a future Berliner Weisse. Made the starter a few days ago and it smells really sour. Lets get into the results.

Water kefir:

Plated my first water kefir on a Sabouraud plate to see what’s in there. I could observe only two kinds of colonies after three days of incubation:

Water kefir bugs on Sabouraud

– Off-white color, even, circular, glossy, convex, 2 mm diameter.

– White color, wavy, irregular, not glossy, flat, 10 mm diameter.

Since I had no idea what these colonies might be, I took a sample of each colony and did a microscopy analysis.

Microscopy picture Water kefir circular colony

And now the really fun part begins: The circular colonies on the agar are no bacteria due to the size of the bugs. These must be some sort of yeasts. Maybe even more than one kind. But a kind of yeast that exists in a slender rather than in a circular form like brewers yeast (aka Saccaromyces). I have no idea what sort of yeast I have here.

Microscopy picture Water kefir wavy colony

And the wavy colonies look even more inhomogeneous than the circular colonies. But these are yeast cells as well due to the size. There are the slender ones again like in the picture above, and a kind of roundish smaller one as well. I have no idea what I got myself here. I expected to find some Lactobacillus bacteria on the plates since bacteria grow much faster than yeasts in general. But I could not find any. And no Lactobacillus on the microscopy samples as well. I guess that Sabouraud agar does not support the growth of Lactobacillus at all.

Comparing the two pictures gives me the impression that there are more than one different kind of yeasts. These results were very unexpected to me and I am quite fascinated what I got myself here.

Lactobacillus starter:

And for the starter: No sign of colony formation at all. Even after further incubation. This might prove that Sabouraud agar is indeed not a media to cultivate Lactobacillus bacteria. Unfortunately I do not have a microscopy picture of the Lactobacillus starter to show the bacteria.

Summary

What did I learn? First, Sabouraud might be unsuitable for cultivating Lactobacillus strains. Second of all, there are some sort of yeasts in the water kefir culture I could not identify further. Lets go back to the results from the first post about the dregs where I could observe only bacteria. The microscopy showed bacteria, Bacillus to be exactly. And I expected that the bacteria might be Lactobacillus or Acetobacter. As these results here showed that Lactobacillus might not grow on Sabouraud, I guess that the bacteria from the dregs must be Acetobacter then.

Did some research about the bugs in water kefir. Some sources state, that there are Candida strains or Kloeckera apiculata in there. I compared my pictures with published pictures of both yeasts and they looked very different to me.

I plated the different colonies on fresh Saboraud plates and will do further investigations.

If there is someone out there who can identify any of the bugs in the pictures, please comment below. And if someone has any ideas how/what to do next with the colonies, please let me know as well.

The next, third post about agar plates will be about some normal Saccaromyces strains.

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Water Kefir tasting

Water kefir the first

Eureka, my first water kefir is ready for tasting. This recipe consisted of: sugar, raisins, water and a water kefir culture. And some lemon juice. I bottled the kefir after fermenting for two days and left it outdoors to keep it cool (it is winter in Switzerland).

Aroma: Smells sweet and some notes of raisins. No sourness detectable.

Appearance: Straw yellow, hazy and some bubbles. No head. Some particles are floating in the liquid.

Flavor: First notes are raisins, some sweetness and a very light hint of sourness. Pretty dry aftertaste. Nice prickling on the palate.

Mouthfeel: Light body and some carbonation. Sweet aftertaste. A real thirst quencher.

Overall impression: This kefir reminds me of a champagne made with raisins. It has Cider notes as well but no apple character. To summarize: it tastes very subtle, only the raisins get through and are very easy to detect.The appearance, well, looks kind of a very cold white wine. The sour sensation might come from the light carbonation of the kefir itself or from the lemon juice.

So, this was my first kefir. I am very fascinated about the character it has. But I would love to get it more sour. I guess two days are not enough to get it sour. The pamphlet, which came with the kefir culture, suggests two days of fermentation to get the best results flavor-wise. I will let it ferment for maybe four days next time and look what happens.

This was a very cool experiment. I already made my second batch with dried apricots instead of raisins. And I will let it ferment for four days instead of two. I might post the tasting notes of the second batch but since this page is not really about kefir… I might leave it with this post about kefir. But I definitely will do further experiments with my kefir bugs. And I will do a Berliner Weisse some times with the kefir culture or at least with some of the bugs from the kefir.

My first Water Kefir

Eureka, the experimenting proceeds. I am planning to do a Berliner Weisse and as it seems that the original Lactobacillus strain seems to be L. brevis for a Weisse. I did some research and found out, that there should be L. brevis in water kefir cultures. So I purchased myself a water kefir culture, and as I was already ordering I bought a Kombucha culture as well, and started my first water kefir today. Will post about my first Kombucha as well.

The kefir recipe was pretty simple: two table spoons of sugar, two table spoons of raisins and some lemon juice to 1 L (0.26 gal) of cold tap water and added the water kefir culture. Thats all. I used a big mason jar as a fermentation vessel.

Water kefir culture (white) and raisins (brown)

The fermentation should take about two days. Since there was not much work involved, I just took some pictures of the culture in the jar. The white stuff are the kefir culture, the brown stuff are the raisins. Really looking forward to tasting the kefir.

And of course, I will take some microscopic pictures of the culture in the future. And in my mind is the thought of a beer fermented with a kefir culture as well… Stay tuned.

01/26/2012: Kefir day. Started the fermentation.

01/30/2012: Tasting

And the microscopy pictures can be found here.