Kefir

25 November 2010 § 4 Comments

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Kefir ready to be poured, kefir grains are swimming on the top by fabrivelas on Zooomr

I got my milk kefir grains on 4 Nov 2010 from one source and on 11 Nov 2010 from another source. They came from sources in Belgium, Australia and Spain, but have been cultured in Belgium for a while. My milk kefir grains are growing relatively fast. I already gave half of them away to a colleague. If I find a way to send them I’ll send some to friends.

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Close-up of a small kefir grain by fabrivelas on Zooomr

At the moment I make 500 ml each day, but if they keep growing I need more than ½ litre or have shorter milk changes. At the moment I am trying to have a rotation of 2 kefir containers going: I take half of the kefir out of each and refill with fresh milk every other day on alternate days, so far I have been using organic cow’s milk, either raw or pasteurised and either full or half fat, depending on what kind of milk I find. My method of making kefir still has to be improved, though.

At the moment I am experimenting with hermetically closing my container, last week I left it open, and it seems that it does not make a huge difference. If I want to stick to my half litre measure, I will have to give away or eat half of my grains every week, so that I have a nice not too fermented kefir after 24 hours.

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Another close-up by fabrivelas on Zooomr

Filtering the kefir grains is not easy because of the curd substance adhering to the grains, so if a strainer is used it has to be shaken quite vigourously, or a wooden spoon or your hand has to be used to stir the grains in the strainer. Shaking the container with the kefir before straining helps, too. There are lots of videos on youtube explaining this.

UPDATE spring 2012
Of course this first batch died in the summer 2011 because of my carelessness, but meanwhile, over Christmas 2011, I got new grains from Canada, that were bought in Germany and I improved my kefir making method: Now I am making a small amount of kefir (100 to 200 ml) for 24 hours outside the fridge with the kefir grains and 24 hours inside the fridge without the grains. I have the kefir jars always closed, never open. I never shake the glass jars. This gives a well tasting kefir. I don’t strain the kefir anymore, I stir and then I just take out the largest kefir grain and re-use it. The smaller pieces that stay I drink with the liquid. At one point I only had 12 very small pieces. Then I used a colander with 4 mm sized holes to strain the kefir.

Origin of kefir

24 November 2010 § 1 Comment

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Small kefir grain by fabrivelas on Zooomr

The origin of milk kefir is described in the paper by M. Motaghi, M. Mazaheri, N. Moazami, A. Farkhondeh, M.H. Fooladi and E.M. Goltapeh, Short Communication: Kefir production in Iran (World Journal of Microbiology & Biotechnology vol. 13 pp. 579-581, 1997):
“A goat-hide bag (4-l capacity) obtained from Pariz and Babak villages in Kerman (Southwest Iran) was washed several times with sterile water, filled with pasteurized milk and intestinal flora from sheep. It was kept at 24 to 26°C for 48 h and shaken hourly. When the milk was coagulated, 75% was replaced with fresh milk. This procedure was repeated for 12 weeks. Gradually a polysaccharide layer (spongy form) appeared on the surface ofthe hide. The layer was removed aseptically from the hides and propagated in pasteurized cow’s milk. Kefir grains of variable size (0.5±3.2 cm in diameter) were added several times to the fresh cow’s milk.”
and also by Semih Otles and Ozlem Cagindi in the paper “Kefir: A Probiotic Dairy-Composition, Nutritional and Therapeutic Aspects” (Pakistan Journal of Nutrition 2 (2): 54-59, 2003):
“Kefir grains are prepared in a goat-hide bag fill[ed](ing) with pasteurized milk inoculated with sheep intestinal flora, followed by culture of the surface layer in milk. Gradually a polysaccharide layer appears on the surface of the hide. The layer is removed from the hides and propagated in pasteurized milk. Kefir grains appear [as] pieces of coral or small clumps of cauliflower florets or pop corn and range from 3 to 20 mm in diameter…”

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Small kefir by fabrivelas on Zooomr

This kefir has to be distinguished from the sugar water kefir (tibi).

The matrix in which the symbiosis of fungi and bacteria grow has been identified as being dextran for the sugar water kefir, whereas for the milk kefir it is kefiran which is made by different kinds of bacteria than those present in the sugar water kefir.

The following summary is from the sugar water kefir page where links to the references are present:
Sugar-water kefir (tibi) forms on the leaves of the Opuntia cactus (orig. Mexico) as hard granules (Lutz, L.: Recherches biologiques sur la constitution du Tibi. Bull. Soc. Mycol. France 15, 68-72 (1899), and Stacey M. and Youd, F.R.: A note on the dextran produced from sucrose by Betacoccus arabinosaceous haemolyticus Biochem J. 1938 November; 32(11): 1943–1945.

These two references seem to be the only ones referring to the origin of the sugar water kefir (tibi) grains which seems a bit strange given the age of the publications. I cannot recall seeing tibi on my grandmother’s Opuntia when it was still living (1990s), but I did not really look for them either.

These sugar water grains have also been identified with the ginger beer plant in other scientific articles (M. Pidoux
(The microbial flora of sugary kefir grain (the gingerbeer plant): biosynthesis of the grain from Lactobacillus hilgardii producing a polysaccharide gel, World Journal of Microbiology and Biotechnology, Springer Netherlands, pp. 223-238, vol 5(2), http://dx.doi.org/10.1007/BF01741847, 1989).)

There has certainly occurred cross-contamination of the two so that even in scientific studies the naming/distinction of the two can differ. I also wonder if different ingredients can change the fungal and bacteriological composition leading to the different names of the sugar water kefir that is tibi, tibicos, water kefir grains, sugar kefir grains, Japanese water crystals, California Bee (from wikipedia) and in older literature also known as Bébées, African bees, Ale nuts, Australian bees, Balm of Gilead, Beer seeds, Beer plant, Bees, Ginger Beer plant, Ginger bees, Japanese Beer seeds and Vinegar bees from Kebler (1921)).
[Kebler, Lyman F. (1921) “California bees.”, J. Pharm. Sci., vol. 10(12), pp. 939-943, http://dx.doi.org/10.1002/jps.3080101206

Sugar-water kefir

12 September 2010 § 14 Comments

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Close up of sugar-water kefir by fabrivelas on Zooomr
This summer I got some sugar-water kefir crystals from the South of France. They have been living there for years of spring water, brown bio sugar and figs. The batch I got have been continuing eating the same ingredients apart from the water which is filtered tap water and mostly rapadura instead of crystallised sugar. I also like to give my kefir ginger, which it seems to like very, very much.
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Sugar-water kefir with cent coin by fabrivelas on Zooomr
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Sugar water kefir in strainer by fabrivelas on Zooomr
As you can see, kefir is not very difficult, it supports a metal strainer contrary to information found elsewhere on the web. The largest crystals that I have seen so far are the size of a little larger than a cent.
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Close up of 5 grains of sugar-water kefir by fabrivelas on Zooomr
In 24 h the amount of kefir doubles on good days. It is quite impressive. The taste of kefir crystals is rather neutral.
This is how I keep the kefir:
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Storage of the sugar-water kefir by fabrivelas on Zooomr

Sugar-water kefir (tibi) forms on the leaves of the Opuntia cactus (orig. Mexico) as hard granules (Lutz, L.: Recherches biologiques sur la constitution du Tibi. Bull. Soc. Mycol. France 15, 68-72 (1899), and Stacey M. and Youd, F.R.: A note on the dextran produced from sucrose by Betacoccus arabinosaceous haemolyticus Biochem J., November 1938; 32(11): 1946–1948.

These two references seem to be the only ones referring to the origin of the sugar water kefir (tibi) grains which seems a bit strange given the age of the publications. I cannot recall seeing tibi on my grandmother’s Opuntia when it was still living (1990s), but I did not really look for them either.

German resumée of the Lutz article:

Lutz, L., Recherches biologiques sur la Constitution
du Tibi. (Bulletin de la Societe Mycologique de France. 1899.
p. 68-72.) 

Unter „Tibi" versteht man kugelige, durchscheinende, wie gekochte
Reiskörner aussehende Massen, die sich in Mexico auf den Opuntien
finden. Sie variiren von der Grösse einer Erbse bis zu der eines
Stecknadelknopfes. In zuckerhaltigem Wasser rufen sie Gährung hervor;
es entsteht ein wohlschmeckendes leichtes Getränk.
Bei der mikroskopischen Untersuchung zeigen sich die Tibikörner
aus Bacillen, Spirillen und Hefen zusammengesetzt. Wenn das gegohrene
Getränk eine Zeit lang ruhig steht, so bilden sich an der Oberfläche
Zoogloeen, die aus Bacillen und Spirillen bestehen. Es ist nicht
schwer zu sehen, dass beide nur Entwickelungsstadien einer Art sind,
indem die Spirillen bald in Bacillen zerfallen. Zur Isolirung der Organismen
empfiehlt es sich, das Getränk zu benutzen und zwar sind flüssige Cultur-
medien geeignet. Indessen hat Verf. die Isolirung auch auf Kartoffeln
durchgeführt.
Man erhält dann einen Kapselbacillus, der sehr variabel in der
Grösse ist (von 1,5 bis 3,3 µ Länge). Die Spirillenform kann die
Länge von 250 — 300 µ erreichen. Der Bacillus ist obligat aërob und
wächst leicht im Tibigetränk, auf Möhren, Opuntia und Heuinfus.
Dagegen wächst er schlecht in Bouillon. In neutraler Raulin'scher
Nährlösung wächst er ebentalls. Von festen Substraten zieht er
Kartoffel vor und Gelatine mit den oben genannntee Flüssigkeiten.
Der Bacillus ist beweglich, producirt kein Indol und färbt sich nicht
nach Gram.
Die Hefe lässt sich leicht in flüssiger oder auf gelatinirter
Raulin'scher Nährlösung züchten. In Möhren und Opuntiainfus
wächst sie ebenfalls. Kartoffel und Möhren sind zusagende feste Nähr-
böden. Die Sporenbildung gelingt in einer Lösung von Candiszucker in
destillirtem Wasser. In jeder Zelle bilden sich vier abgerundete Sporen,
die leicht wieder auskeimen.
Um die ursprüngliche Symbiose in den Körnern wieder herzustellen,
verfährt man so, dass man in Möhrenabkochung den Bacillus impft.
Nach einigen Tagen zerreisst man durch heftige Bewegung des Cultur-
gefässes die Bakterienhaut und impft die Hefe ein. Es bilden sich nun
Körner, indem die Bacillen die Hefezellen einschliessen. Durch vor-
sichtige Zuckerzufügung lässt sich der Process sehr lange fortsetzen.
Beide Organismen vermögen zusammen die Gährung einzuleiten und zu
unterhalten, während einer allein es nicht kann.
Es ist wahrsclieinlich, dass beide Organismen neu sind. Bevor
Verf. aber eine definitive Beschreibung giebt, stellt er weitere Unter-
suchungen über ihre Eigenschaften und die von ihnen erzeugte Gährung
in Aussicht.
                                                       Lindau (Berlin)
(from a summary in: Beihefte zum Botanischen Centralblatt, Cassel, vol 9 (2), 1900, Verlag von Gebründer Gotthelft.)


Lutz writes also in 1906 about the symbiotic associations of saccharomyces Radaisii here is a summary of his article:

Lutz. — Associations symbiotiques du Saccharomyces Radaisii (Bull. Soc. inje. l906, p. 96). 

Le Tibi, dont on se sert an Mexique pour obtenir une liqueur fer-
mentée, est constitué par des masses sphéroïdes dont le centre est
occupé par le Saccharomyces Radaisii et la périphérie par le
Bacillus Mexicanus. Le rôle de ce bacille consiste uniquement
à préserver contre le contact de l'air le Saccharomyces, qui est un
organisme anaérobie. 

L'auteur a, en effet, réussi à opérer une symbiose analogue en
associant ce Saccharomyces au Bacillus subtilis. Ce dernier bacille
enveloppe de toutes parts le Saccharomyces qui, ainsi préservé
contre le contact de l'air, végète et fonctionne comme ferment. 

La seule différence importante que l'on constate, suivant que l'on
emploie l'un ou l'autre bacille, est le développement, avec le Bacil-
lus subtilis, d'une odeur marquée rappelant la groseille. Ce « bou-
quet » peut d'ailleurs être extrait par agitation avec de l'éther et
évaporation du solvant. 

Dans un précédent travail (1), M. Lutz avait déjà constaté que le
Saccharomyces du Tibi, cultivé sur divers milieux sucrés, pousse en
aérobie et ne produit aucun dégagement de bulles gazeuses; qu'au
contraire, en milieu gélatine (bouillon do carotte gélatine placé
dans une étuve à 30°, de manière à conserver l'état liquide), ce
Saccharomyes produit une fermentation active. 

Le rôle des deux organismes du Tibi est ainsi expliqué. En
culture aérobie, la levure vit aux dépens du sucre ou de toute autre
matière carbonée : l'oxygène lui vient abondamment de l'air et elle
n'a nul besoin de brûler le sucre pour s'en procurer. En culture
anaérobie, au contraire, elle fait fermenter le milieu et décompose
le sucre pour y puiser l'oxygène nécessaire à sa vie. 

Rappelons à ce sujet que d'autres ferments (Saccharomyces) vi-
vent en symbiose avec des Bacilles, par exemple celui du Képhir
{Rev. mycol, XIV,161, du forment de la bière de Gingembre
(XV,33) et celui du Leben d'Egypte (XXV, p. 55). (1) Lutz. Nouvelles recherches sur le Tibi. (Bull. Soc. mycol. 1899, 157).

from REVUE MYCOLOGIQUE JANVIER 1906 (28th year, number 109).

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