Experiments 1: Mass Murderer

I am of German origin. German cuisine is special (as is the cuisine of every other country as well). I am not talking about sausages. (Fried and grilled) sausages are part of the cuisine of many countries.

I am not talking about barbecue either. Germans think of themselves as the world champions of barbecue. They are not, not even close. They just deny of the mere existence of barbecues and grills outside of Germany. This makes Germans world champions of barbecue in their own perspective. And no, not even your ridiculous Weber Grill helps. Ever noticed, that "Weber" sounds German, but is an US American company? Go figure...

I am not talking about beer. It is true, Germans tend to drink a lot of beer and there is a large variety of beers, but look at the Belgian and you will find out, that there are other countries with a better choice of beers. Ever seen the average Argentine serving, if you order "para tomar una cerveza, por favor"? Germans would be very surprised to see, that there are countries, where the single serving of a beer is about two to three times the amount you get in Germany (if you order a beer in Argentina without specifying the size of it, you get a 1 liter bottle of beer; in Germany those do not even exist). Yes, the Germans have their infamous Oktoberfest in Munich, but have you ever noticed that about 90% of the visitors are US Americans, Japanese, British and Indian? The 10% of German visitors are usually staying at the Weinzelt not having beer at all...

I am not talking about bread. It is true, Germans do have specific types of bread, that you do not easily get somewhere else. Ever noticed, that the same applies to other countries (see Injera, Hallulla, Naan, Melonpan, Sac Ekmeği)?

I am more talking in terms of diet actually. The typical German diet includes lots of dairy products. There is a broad variety of dairy products available. And I have never seen such a rich variety of dairy products in any other country.

A major part of my personal daily diet in Germany consists of (non-flavored) yogurt and curd (particularly quark). I typically eat curd and fresh fruit as part of my Müesli in the morning (if I am having breakfast at all). I like yogurt to be part of my salad dressings and as a generic ingredient of my lunch. I adore a proper Ayran or Lassi for drinks. In the evening I typically eat at least 500 grams of non-flavored yogurt without anything else. Besides that I of course eat all kinds of cheese (yes, all of them) and all other kinds of processed (meaning soured, filtered, concentrated, coagulated) and non-processed varieties of milk. I die for fresh raw milk bought from a farmer directly (preferably with the slightly warm body temperature of a cow, i.e. freshest). No, I am not a pervert. I just like my food to be of a rich, natural (!) and pure flavor.

Why am I telling you all of that? Because it seems that most other cultures do not appreciate yogurt and curd as much as I personally do. Staying here in Argentina I can buy lots of yogurt. They have got huge coolers with yogurt, all artificially flavored. If I am lucky, they have got this one brand that provides non-flavored yogurt for a ridiculously high price (compared to the flavored varieties). So there is a huge shelf with what feels like 250 different types and brands of flavored yogurt. And somewhere in the darkest corner of this shelf, there is my precious: a single 190g (hilarious! I could inhale that in under two seconds!) pack of non-flavored yogurt for - believe it or not - 9 friggin' pesos (where you get the same amount of flavored yogurt for about 5 pesos right now). And I am like YAAYY! And it's close to the expiry date, but I don't care, because I've got my precious and I am running to the cashiers to save the final, the ultimate pack of 190g of non-flavored yogurt and I am the happiest man in the world...

...and... no curd! ... I repeat: no curd! ... They are not selling curd here. Nothing. Never. No supermarket provides curd. No deli shop provides curd. No health food shop provides curd. No curd!... It's like: NOOOOO, por faVORRR! And I feel my body craving for curd. I am like a man lost in the desert: curd! CURD! I NEED CURD!... but in this matter the Argentine are just utterly relentless...

So when I was back in Germany I planned to bring lots of non-flavored yogurt and curd with me. But then I figured, that it might not be the best idea to do so taking flight security regulations into account. Suddenly it hit me: I have to prepare my own yogurt and curd! Heureka! That is the solution of my curd dilemma.

So there I was, 39 going on 40 not having the slightest clue of what might be the actual difference in the production of yogurt and curd, but determined to finally overcome all obstacles and provide myself with a proper dairy diet in Argentina. I knew, that both yogurt and curd where kind of "sour milk" and I knew, that some kind of bacteria are involved in producing yogurt. I knew, that curd is often mistaken for yogurt, but it is really not the same. Nobody was able to provide answers to me (with the exception of my dearest sister, whose studies of food sciences sort of helped). I actually had to do some additional research to find out, that

• yogurt is basically milk soured and fermented with the help of lactobacillales without any further processing. Particularly Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus are used as the starter cultures. These define the product "yogurt". Lactobacillus acidophilus, Lactobacillus subsp. casei, and Bifido-bacteria may be added to yogurt as probiotic cultures.
• Curd is a very immature state of cheese production, which is made from fermented milk by coagulating (curdling) milk proteins with the use of enzymes/rennet, acid treatment (e.g. for Cottage cheese, Quark (!), and Cream cheese) or heat-acid treatment (e.g. Paneer, Ricotta and Queso Blanco) . The bacterial cultures used to start the fermenting process for curd includes (but is not limited to) the ones that are used for yogurt.

Lactobacillales

So what is the actual difference? Yogurt starter cultures by definition contain Lactobacillus bulgaricus and Streptococcus thermophilus. The product "yogurt" is finished with the fermentation of milk with these specific bacteria reaching pH 4.5. Fermentation is stopped by cooling down the fermented milk to below 7°C. Curd on the other hand makes use of a broad variety of unspecified Lactobacillales. It is the result of both the fermentation and curdling process steps.

Fun Facts:

• The curdling automatically sets in at some point of the fermentation process due to the increasing acidity of the fermented (i.e. soured) milk.

• Neither curd nor yogurt are considered to be truely probiotic as per FAO/WHO regulations, although both contain living microorganisms. To be classified as a probiotic a product must be or must contain live microorganisms (generally numbering one billion) which are resistant to gastric acid, bile and pancreatic juices and reach the target site (small intestine/large intestine) in numbers sufficient enough to elicit a beneficial effect. The number of available live microorganisms for curd is not quantified. The yogurt producing bacteria are not considered probiotic. This in turn means, that probiotic yogurt is a product, where probiotic microorganisms have been added to the original yogurt in sufficient amounts and that the beneficial effect of the final product has been clinically tested.

• Curd produced by coagulating fermented milk via acid treatment is usually more fragile then rennet processed curd, because of the loss of calcium.

• Henceforth, curd produced by heat-acid treatment retains 90% of the protein available in the milk instead of only about 70% with rennet treatment. This is due to the fact that whey proteins usually are not affected by acid coagulation. If there is a heat treatment, the whey proteins become sensitive to acid coagulation. This in turn means, that a higher amount of protein can be retained.

All this knowledge could be gathered thanks to Cornell University (Yogurt, Cheese) and furthermore to the very detailed descriptions of The Dairy Science and Technology eBook of the University of Guelph, Canada.

So with all of this knowledge I tried two simple recipes:

 Homemade Yogurt

1. prepare milk by heating it up to 90°C max. (no cooking!)
2. let it cool down to 42°C max.
3. add living yogurt cultures (you just buy fresh natural yogurt and stir a spoon of it into the warm milk for inoculation)
4. keep the temperature for the inoculated milk between 30° and 42° for at least 4 to 7hrs and let the milk ferment
5. put the stuff in the fridge to stop fermentation

Homemade Curd

1. buy milk (1l)
2. pour the juice of one lemon (or lime) into the milk and stir
3. give the stuff 30mins to 1hr to coagulate
4. filter the whey (if you want to get rid of
5. put the stuff in the fridge

Trying out the yogurt-making for the first time was the ultimate success. In no time I had 1kg of proper yogurt. The taste of the yogurt was quite close to the original I bought. Everything seemed to be perfect. Problem through the process was, that I do not have a thermometer available. I basically had to guess temperatures. Apparently my guessing was pretty good.

When I went for the production of the second kilogram of homemade yogurt, the disaster happened. My temperature guessing was not very good. Apparently the milk was not cool enough as per step 2 of the recipe. I added the bacteria a little too early. And so I became a mass murderer. Millions of Lactobacillus bulgaricus and Streptococcus thermophilus were burned to death in a second. And I did not even realize it. So I kept all the corpses cosy and warm for the next 7hrs, because I thought they would live the perfect bacterial life and prosper and ferment. But in the end: nothing, just 1 litre of sterile milk with millions of bacteria corpses. Single-handedly I killed a whole (yogurt) culture.

"I can see dead bacteria."

Tried to make curd from it by pouring the lemon juice into it. Coagulation kinda worked. In the end I had a "soup" of partly coagulated dead yogurt bacteria in sterile milk. Filtered it. The taste was... ... okay. The texture was not.

Rewind. Repeat.