The CC received a clay pot as a gift recently.
It was a classic meen chatti (मीन चट्टी - literally: fish clay pot). The first word is from Sanskrit (= fish) and the second most likely from the local vernacular.
Instructions were provided to "season it" but the CC needs to understand what that means so he proceeded down the rabbit hole (as he is wont to do) about what that really entails.
Clay is quite porous as a material. However, it can be fired at high temperatures after which it becomes hard. That's how bricks are made which has been known since at least Sumerian times.
Clay is also an extraordinarily poor conductor of heat.
These combined facts act as an advantage in fish cookery.
The critical point about a clay pot is that no matter how hard you try to heat it in a reasonable time (= less than five hours, for example), it's very difficult to raise the temperature of the interior of the pot to above 70°C† — which is the outer limit of the temperature that fish proteins denature.
Of course, if you fired the crap out of the pot, eventually it would rise to the temperature of the flame but we're talking cooking here not cremation!
The other critical point is that if you don't raise the temperature beyond the denaturation point of fish proteins, they will stay soft independent of the cooking time. If you held the temperature precisely at a certain point, your fish would stay perfectly tender whether you cooked it for ten minutes or ten hours!
This is how airlines control food, for the record. The temperature is never allowed to get above the denaturation point of the proteins in question — chicken, beef, fish, vegetables, whatever!
The principle of clay-pot cooking is the same as that of sous-vide cooking except that it is being done in an intuitive way rather than formally. It also has a massive advantage over sous-vide in that you can fry or sear the fish and have it cook in the complex juices generated by it. You don't need to worry about the problem of precise timing either which was a useful fact in the frenetic frazzled world of yore unlike modern day times.
There's a price to be paid for this freedom. Nothing comes for free.
The pot is a complex apparatus. If you drop one of your metal pots, it'll get dented. If you drop a clay pot, it shatters and you get to start all over again. (Luckily, they are cheap but that's not the point.)
Poor conduction also goes both ways. It's really hard to raise the temperature and it's equally hard to lower the temperature. A certain boring-ness is required in the usage of a clay pot. You can't just dial the temperature up and down like a metal pot.
Much more importantly, you can't add hot water to a cold pot, or cold water to a hot pot. It will crack. The poor conduction means you cannot have the interior and the exterior at significantly different temperatures.
The seasoning of the pot is really quite simple once you grasp the concepts. You alternate boiling cold water in the pot and toss it out followed by coating it with cooking oil overnight. The water percolates through the pot and mends micro-holes in the clay and the oil conducted via the water generates enough carbon residues to plug the holes. It also generates a non-stick surface at the bottom of the pot over time (exactly like a great cast-iron frying pan.)
There are two fallacies about clay pots and since chez CC, we tend to be the analytic sort, we're going to dismiss them.
The first is that the seasoned clay pot is not porous — it absolutely is! The water inside the seasoned pot has to be going somewhere. It's not evaporating significantly at 70°C‡ so it must be disappearing somehow. It's evaporating through the porosity of the pot. It's being wicked§ away.
This porosity created a bit of a problem for the CC in the second round of water seasoning when the pot had been coated with oil overnight. Enough oil/water was being wicked away through the porous clay that the CC's gas flame went a little crazy. It's basically a baby version of a grease fire. It was such a minuscule amount of oil that it posed no risk whatsoever but it was quite unnerving until the principles had been grasped.
The second which is really the flip of the first is the myth that you can't cook in a dry pot without water. You absolutely can as long if you want to raise the temperature above 70°C. You could quite plausibly cook the clay pot to up to 1000° C but the CC really doubts that your puny stove generates enough BTU's for that. (Your oven only goes up to 275°C!)
Remember, if you do amp up the temperature of the pot, you will not be able to add cold water to it. You must either cool the pot down and start over or heat the water to the same temperature and add it. Most cooks do the former not the later since it's too risky.
In fact, many recipes ask you to first boil stuff till the water disappears, take the fish out, and then use the pot just like a frying pan adding the fish back at the last step. (The reverse is also true. Some recipes ask you to use it like a frying pan and then add the fish and warm water a little at a time thus lowering the temperature back down.)
Let's abstract out the principles of the perfectly seasoned clay pot.
[1] With water inside, the temperature will not go above 70°C until the water disappears.
[2] The clay pot is a very poor conductor of heat.
[3] The dry clay pot will allow you to fire it up to 1000°C.
Now that we've grasped the principles, we're ready to roll.
One of the great glories of Mughal cooking is the perfectly cooked daal. This involves the denaturing of lentil proteins and some of these lentils tend to get slimy if the skins split. The clay pot is the ideal apparatus since it preserves the skin perfectly while letting the water and spices to enrich the dish via osmosis but not allowing the lentils to burst.
The truly great dish of Gujarati cooking is undhiyu (ઊંધિયું — literally: upside-down.) The Mughals totally envied this dish! It's a classic mélange of spring vegetables, complex vegetarian meatball-esque preparations, and spices cooked in a sealed upside-down (sic) pot in the dying embers of a fire overnight at low heat. Same logic goes for long-term low-temperature cooking and the denaturing of the proteins.
If you go to North India during winter, you'll find yogurt served in clay pots. The clay pots are being used for two purposes — heat preservation and water-evaporation. Even in the cold temperatures of the North-Indian winter, the clay pots retain the heat of the warm mixture of milk and bacteria¶ and wick away enough water to make the yogurt rich and delicious.
So this device which is at least 20,000 years old (based on Chinese excavations that date back to 18,000 BC) is truly a magic apparatus. It just requires a little understanding.
We're just the latest in a truly ancient lineage.
† You can verify this quickly and empirically by sticking a finger for less than a second into the water that has been boiling in the clay pot for an hour. Nothing much will happen. If you stuck your finger in real boiling water for even less than a second, you would get second-degree burns!
‡ The CC will not bore you with the details but roughly speaking in an environment with no air-flow (e.g. your exhaust fan) the evaporation rate is linear in the temperature differential between water and air for temperatures around 100°C. Estimating your house to be about 25°C (80°F), you are only getting roughly 60% of the evaporation of boiling water. The rest of the water has to be going somewhere!
§ You can test this by covering a pot and heating water in it. It will never boil but soon much of the water will be gone.
¶ The clay pots have the advantage of porosity. The yogurt bacteria are sitting in there and they help develop the culture implicitly particularly if you make yogurt every day or week in the same pot. (The clay pots that they use are small. Individual use, one might say, in modern parlance.)
Showing posts with label yogurt. Show all posts
Showing posts with label yogurt. Show all posts
Monday, April 24, 2017
Wednesday, May 7, 2014
Bacterial Overload
Recently the CC went to one of those outdoor street fairs where there was a pickle stand. They were also selling some of the pickled juice blended with tomatoes as a "Bloody Mary Mix". The vendors kept apologizing and warning clients who wanted to buy it that it was not pasteurized.
And the CC was completely nonplussed, "So it has come to this?"
It doesn't need to be pasteurized!
There is a fundamental lack of understanding by people who work in food about our relationship with other bio-agents and particularly the organisms that we are deeply symbiotic with namely bacteria.
At this point in time, advertising agencies have basically convinced consumers that bacteria are "evil" but nothing could be further from the truth.
The standard mechanism of cultivating bacteria in the lab is creating something called a "culture". Basically, a swab of bacteria are grown on a substrate and then examined under a microscope. Based on this, it was estimated that something like 1% of a human mass was actually bacteria. Little did people know how wrong this estimate turned out to be.
In the early part of the 21st century, the price of DNA sequencers fell precipitously. What used to be an expensive tool became dirt cheap. Scientists had the entirely brilliant idea of not measuring bacteria by mass but by what percentage of DNA of our body was made up of bacteria. Turns out the answer is between 90-99%.
Remember the two estimates are of different things. One is by weight and the other is by percentage of DNA that is non-human. They are different things but the latter estimate is clearly the more important.
To put it differently, we humans exist for the benefit of the bacteria not the other way around. Of course, we are extraordinarily symbiotic with them. We provide them the food and they provide us both protection by repelling all the "bad bacteria" and do significant portions of body work for us.
In fact, the bacteria on your left and right hands are completely different.
So why did the earlier scientists get it so wrong? How can the estimates be so off?
You should be able to guess the answer. Not every bacteria can grow in the "culture". In fact, they can only survive in that localized environment inside the body that they have adapted to.
The answer is even more complex. There's no such thing as "good" or "bad" bacteria. It's contextual. You move the "good" bacteria from the right spot where they are supposed to be into the wrong spot and they will become "bad" bacteria. The context is completely important.
The bacteria that we are the most symbiotic with is a family called lactobacillus. Every time, you eat yogurt, eat or drink miso, eat pickles, cheese, kimchi, drink beer or wine, you are basically consuming them in vast quantities. They do the fermentation for us, and in turn, they repel other harmful bacteria for us. We are completely reliant on them.
So now maybe you can guess why the pickled juice blended with tomatoes did not need to be pasteurized?
The lactobacilli would repel any invader which there are not that many of to start with because of the acidity of the environment. The lactobacilli are the rare family that has adapted to the acidic environment thanks to their symbiosis with us.
Fermented foods have a long history of being considered "good for you". It was just an empirical observation over large swathes of human history in vastly different regions and contexts but they all came to the same conclusion.
Only in the 21st century is science able to actually dissect how all these various extraordinarily-complex mechanisms actually work.
But the CC's point is a lot larger. How have we gotten to a point where the most basic food interaction is fraught with anxiety? The answer is that Madison Ave. has made you paranoid.
The CC never relies on the expiration dates for milk. Just smell it. It's pretty obvious. Sometimes it will go bad before the expiration date!
The same goes for fermentation and fermented products. They work in a complex way and made correctly will last forever. Experienced picklers never throw out the juice. They use a cup of it to start off the next batch because it has the complex blend of bacteria all ready to give the next batch the right start.
Pickling is one of the greatest achievements in food technology. Just remember that for most of human history, humans were food deprived. Our modern calorie-rich environment is an extraordinarily recent development barely 50 years old. Pickling was the trick that allowed humans to store food for the winter. It also gave variety and complexity to their diet and the symbiotic relationship with the bacteria made for healthier humans.
The CC hopes that this explanation convinces people not to think of bacteria as "evil" but our necessary partners in the game of life. We need them; they need us. We can't actually function without them.
So the next time you're at the fair eating a pickle-on-a-stick, you should not think to yourself "Ooh! crunchy cucumber", you should really be thinking "Ooh! Tons of bacteria with a side helping of crunchy cucumber!"
And the CC was completely nonplussed, "So it has come to this?"
It doesn't need to be pasteurized!
There is a fundamental lack of understanding by people who work in food about our relationship with other bio-agents and particularly the organisms that we are deeply symbiotic with namely bacteria.
At this point in time, advertising agencies have basically convinced consumers that bacteria are "evil" but nothing could be further from the truth.
The standard mechanism of cultivating bacteria in the lab is creating something called a "culture". Basically, a swab of bacteria are grown on a substrate and then examined under a microscope. Based on this, it was estimated that something like 1% of a human mass was actually bacteria. Little did people know how wrong this estimate turned out to be.
In the early part of the 21st century, the price of DNA sequencers fell precipitously. What used to be an expensive tool became dirt cheap. Scientists had the entirely brilliant idea of not measuring bacteria by mass but by what percentage of DNA of our body was made up of bacteria. Turns out the answer is between 90-99%.
Remember the two estimates are of different things. One is by weight and the other is by percentage of DNA that is non-human. They are different things but the latter estimate is clearly the more important.
To put it differently, we humans exist for the benefit of the bacteria not the other way around. Of course, we are extraordinarily symbiotic with them. We provide them the food and they provide us both protection by repelling all the "bad bacteria" and do significant portions of body work for us.
In fact, the bacteria on your left and right hands are completely different.
So why did the earlier scientists get it so wrong? How can the estimates be so off?
You should be able to guess the answer. Not every bacteria can grow in the "culture". In fact, they can only survive in that localized environment inside the body that they have adapted to.
The answer is even more complex. There's no such thing as "good" or "bad" bacteria. It's contextual. You move the "good" bacteria from the right spot where they are supposed to be into the wrong spot and they will become "bad" bacteria. The context is completely important.
The bacteria that we are the most symbiotic with is a family called lactobacillus. Every time, you eat yogurt, eat or drink miso, eat pickles, cheese, kimchi, drink beer or wine, you are basically consuming them in vast quantities. They do the fermentation for us, and in turn, they repel other harmful bacteria for us. We are completely reliant on them.
So now maybe you can guess why the pickled juice blended with tomatoes did not need to be pasteurized?
The lactobacilli would repel any invader which there are not that many of to start with because of the acidity of the environment. The lactobacilli are the rare family that has adapted to the acidic environment thanks to their symbiosis with us.
Fermented foods have a long history of being considered "good for you". It was just an empirical observation over large swathes of human history in vastly different regions and contexts but they all came to the same conclusion.
Only in the 21st century is science able to actually dissect how all these various extraordinarily-complex mechanisms actually work.
But the CC's point is a lot larger. How have we gotten to a point where the most basic food interaction is fraught with anxiety? The answer is that Madison Ave. has made you paranoid.
The CC never relies on the expiration dates for milk. Just smell it. It's pretty obvious. Sometimes it will go bad before the expiration date!
The same goes for fermentation and fermented products. They work in a complex way and made correctly will last forever. Experienced picklers never throw out the juice. They use a cup of it to start off the next batch because it has the complex blend of bacteria all ready to give the next batch the right start.
Pickling is one of the greatest achievements in food technology. Just remember that for most of human history, humans were food deprived. Our modern calorie-rich environment is an extraordinarily recent development barely 50 years old. Pickling was the trick that allowed humans to store food for the winter. It also gave variety and complexity to their diet and the symbiotic relationship with the bacteria made for healthier humans.
The CC hopes that this explanation convinces people not to think of bacteria as "evil" but our necessary partners in the game of life. We need them; they need us. We can't actually function without them.
So the next time you're at the fair eating a pickle-on-a-stick, you should not think to yourself "Ooh! crunchy cucumber", you should really be thinking "Ooh! Tons of bacteria with a side helping of crunchy cucumber!"
Thursday, March 7, 2013
Yogurt Updates
No post seems to have generated the sheer amount of comments and updates as the yogurt post just a few days ago.
Speaking of which, ladies and gentlemen, could you please post your comments publicly so that everyone can share?
You know who you are. Don't make the CC shame you.
Here's the best of the list:
[1] 2% organic milk works best.
CC: Experimentally verified and confirmed!
[2] If you have a pizza stone, pre-heat the oven to about 200°F for about 2-3 hours. If the stone is on a different shelf than the container, it will ensure that the oven stays warm at the desired even temperature of 180°F even in the coldest winter.
CC: DUH!!! Simplicity itself. How obvious in retrospect.
[3] If you want a thicker yogurt without the fat, add in some milk powder when boiling the milk.
CC: Not tried but makes complete sense.
[4] If you want "Greek yogurt", you must drain the fresh yogurt in a cheese cloth for about 6-8 hours.
CC: Yep! and the drained whey is muy muy delicioso! Do not waste.
Speaking of which, ladies and gentlemen, could you please post your comments publicly so that everyone can share?
You know who you are. Don't make the CC shame you.
Here's the best of the list:
[1] 2% organic milk works best.
CC: Experimentally verified and confirmed!
[2] If you have a pizza stone, pre-heat the oven to about 200°F for about 2-3 hours. If the stone is on a different shelf than the container, it will ensure that the oven stays warm at the desired even temperature of 180°F even in the coldest winter.
CC: DUH!!! Simplicity itself. How obvious in retrospect.
[3] If you want a thicker yogurt without the fat, add in some milk powder when boiling the milk.
CC: Not tried but makes complete sense.
[4] If you want "Greek yogurt", you must drain the fresh yogurt in a cheese cloth for about 6-8 hours.
CC: Yep! and the drained whey is muy muy delicioso! Do not waste.
Monday, February 25, 2013
Making Yogurt
Making yogurt is so straightforward that the CC is surprised it's not more commonly known. When the CC was making it, two separate people commented on the fact the milk will get "spoilt".
Well, DUH!
Yogurt is spoiled milk. So is cheese for that matter. So are miso, kimchi, and all other sour pickles. It's the precision of the spoilage that matters not the fact that it's "spoilt."
Good grief.
Ladies and gentlemen, boys and girls, yogurt doesn't come from the supermarket. It's spoilt milk and it's important that it be "spoilt" in the right way.
Over millenia, we as a species are symbiotic with a class of bacteria known collectively as lactobacilli. (Literally, milk-bacteria.)
We co-exist and they do wonderful things for us in our guts. That's why antibiotics make you feel so queasy at the end of the dose. They wipe out all the bacteria in our body and we can no longer digest anything that well. (Incidentally, a lot of what we consider "digestion" is being done by the bacteria in our gut not by humans but's that for a different post.)
Anyway, making yogurt is dead straightforward. The only hard part in winter is setting it in a warm enough place.
Ingredients
4 cups milk
1/2 cup active yogurt
Recipe
Heat the milk in a non-reactive pan until it comes to just under a boil. You are both killing all the other bacteria present in the milk and changing the proteins to be more receptive to making yogurt.
Cool the milk down to about 110°F (just above human temperature.) The old wives' method is to see if a finger inserted in the milk is comfortable or not. Above this temperature, you will kill all the bacteria introduced later.
Add the yogurt and whisk it into the milk. You are basically doing a precise "spoilage".
Let it sit in a warm spot for about 8 hours. It takes less time in summer and a little longer in winter.
Refrigerate and repeat.
Well, DUH!
Yogurt is spoiled milk. So is cheese for that matter. So are miso, kimchi, and all other sour pickles. It's the precision of the spoilage that matters not the fact that it's "spoilt."
Good grief.
Ladies and gentlemen, boys and girls, yogurt doesn't come from the supermarket. It's spoilt milk and it's important that it be "spoilt" in the right way.
Over millenia, we as a species are symbiotic with a class of bacteria known collectively as lactobacilli. (Literally, milk-bacteria.)
We co-exist and they do wonderful things for us in our guts. That's why antibiotics make you feel so queasy at the end of the dose. They wipe out all the bacteria in our body and we can no longer digest anything that well. (Incidentally, a lot of what we consider "digestion" is being done by the bacteria in our gut not by humans but's that for a different post.)
Anyway, making yogurt is dead straightforward. The only hard part in winter is setting it in a warm enough place.
Ingredients
4 cups milk
1/2 cup active yogurt
Recipe
Heat the milk in a non-reactive pan until it comes to just under a boil. You are both killing all the other bacteria present in the milk and changing the proteins to be more receptive to making yogurt.
Cool the milk down to about 110°F (just above human temperature.) The old wives' method is to see if a finger inserted in the milk is comfortable or not. Above this temperature, you will kill all the bacteria introduced later.
Add the yogurt and whisk it into the milk. You are basically doing a precise "spoilage".
Let it sit in a warm spot for about 8 hours. It takes less time in summer and a little longer in winter.
Refrigerate and repeat.
Monday, September 10, 2012
Raita with Cherry Tomatoes & Chives
Authenticity be damned, the CC damn near ate the entire thing while tasting it!
(It's not that far removed from a classic onion and tomato raita. So there!)
Ingredients
1 cup Greek yogurt
12 red cherry tomatoes
12 yellow cherry tomatoes
1/4 cup chopped chives
salt
black pepper
Recipe
Quarter the tomatoes. Toss everything together. You may need to add a few tablespoons of water to get the desired smooth consistency.
(It's not that far removed from a classic onion and tomato raita. So there!)
Ingredients
1 cup Greek yogurt
12 red cherry tomatoes
12 yellow cherry tomatoes
1/4 cup chopped chives
salt
black pepper
Recipe
Quarter the tomatoes. Toss everything together. You may need to add a few tablespoons of water to get the desired smooth consistency.
Thursday, June 17, 2010
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