Category Archives: food

Tea for December: Week 2

Leave a reply

The tea consumption continues! This weekend I went to the shop and got adventurous. It’s going to be a flavorful December! Some days I revisit an old stand-by, some days I try something brand new. Every day I learn something new about tea. This week, I tried straight Assam tea for the first time, and had my first Taiwanese and Thai teas.

Little tea factoid of the week

Tea all comes from the camellia sinensis plant. There are two subspecies: var. sinensis and var. assamica. Sinensis is the Chinese version that has been cultivated in China for many centuries. Assamica was first globally known in 1823, found in eastern India.

Before the discovery of Assam tea, China supplied Britain with tea. Britain really wanted tea, but China only wanted silver bullion in return. Britain began introducing opium to China to create demand for a product more easy to produce than bullion. Between 1821 and 1837, British delivery of opium increased fivefold. During this time, Britain also began extensive tea plantations in India. Britain got their tea fix and China went on to suffer the Opium Wars.

Today, Assam tea is still grown in the Assam region of India. It’s maltier in flavor, and if you’ve had English Breakfast tea, you’ve probably had a blend with some Assam tea. I don’t drink my tea with milk, but Assam tea is supposed to be especially good with it.

week2

This slideshow requires JavaScript.

Advertisement

Tea for December: Week 1

Leave a reply

It’s been an exciting week of teas. Someone said my project sounded like an advent calendar, so I decided I could make that work. I’ll continue to fill it out as the month proceeds. I’ve been posting my drink every day on Twitter; you can find my feed on the right side of my home page.

Little Tea factoid of the week

Do you know what oolong tea is? Oolong tea is partially-oxidized tea. When you leave an apple on a table and it turns brown, that’s oxidation. Green tea is unoxidized, and black tea is fully oxidized. (The oxidation process is fancier than letting it sit out, but that’s the basic chemistry.) Oolong is the tea in between. There are green oolongs (less oxidized) and black oolongs (more oxidized). Above all else, oolongs are delicious.

first_week_tea.jpg

This slideshow requires JavaScript.

Tea for December

Leave a reply

I love tea. Even in elementary school I began the day with tea; when I was little I drank herbal and eventually I transitioned to true-blue camellia sinensis. Today I drink about 3 liters of tea every day. It starts and ends and fills my day with joy. When my stomach was upset, when I was on a restricted medical diet—tea was there. On my desk right now I have a Darjeeling 2nd Flush black tea and a sweet Genmaicha green tea (green tea with roasted rice in it). I am drinking English breakfast tea with rose that I brought from home.

Only recently did I seek to learn more about tea. I knew I liked black teas and smoky green teas and, with that constraint, I’d go to the tea shop, sniff around (literally), and pick out some winners. I realized that, other than the flavor, I didn’t know anything about the teas I was drinking. What made them different? Could I find more teas that I would love if I could understand my tastes better? I bought a copy of Tea: History, Terroirs, Varieties, from which I learned about where tea is grown, what kinds of tea each country grows, and how they differ.

As with everything, I get into habits with my tea drinking. Lately, I drink English breakfast tea (EBT!) with rose most mornings. For a strong treat, I drink New Vithanakande Ceylon black tea. For a fancy treat, I drink Yunnan Golden Buds black tea. For a mellow treat, I drink Tie Guan Yin Oolang tea. My local tea shop, New Mexico Tea Company, is wonderful.

So this December I plan to drink a different tea every day. December is a wonderful time to drink warm drinks. Tea is a calorie-free treat in a season filled with pies and cookies and roasts. And tea is delicious and it’s a good way to try new things.

Suggestions (especially of fancy blacks) and fellow tea drinkers are welcome! Happy drinking!

The FODMAP Diet: An IBS diet based upon peer-reviewed science

Leave a reply

I’m extremely lactose intolerant. What this means, biologically, is that I no longer produce enough lactase to process lactose sugar. Because I can’t process lactose in my small intestine, it moves on intact to my large intestine where bacteria eat the sugar. The byproduct of their digestion, gas, causes bloating, pain, cramping and, well, you know the rest.

What is IBS and what causes it?

Irritable Bowel Syndrome (IBS) is an incredibly common malady, affecting 6-46% of the population, depending upon the study. It’s a diagnosis resulting from the lack of a diagnosis; it’s diarrhea, bloating, stomach pain, and cramping that can’t be explained by celiac disease, lactose intolerance, fructose intolerance, or other understood gut disorders.

IBS is thought to be caused by visceral hypersensitivity, or over-sensitivity to pressure on the intestines. Imagine two people eat broccoli and get a bit gassy: the person with IBS would feel pain and discomfort while the other person might be bloated but otherwise fine.

It’s often implied that IBS is psychological as much as physiological. Anxiety and depression are common in people with IBS. In my experience, the perceived psychological component, the lack of simple treatments, and the lack of life-threatening consequences can lead doctors to be blasé about IBS. They recommend fiber, exercise, and routine, and shrug if that does little. Small wonder that people might feel blue. But gut science is improving, and the FODMAP approach is a new and widely successful strategy for reducing the symptoms of IBS.

What is the FODMAP approach, and what is different about it?

The FODMAP diet is based upon known biochemistry and the hypothesis that visceral hypersensitivity causes IBS. There are many molecules that, like my undigested lactose, tend to be digested in the large intestine and produce gas. The FODMAP diet eliminates a wide range of such molecules.

FODMAP, introduced in 2005 by Monash University, is a peer-reviewed diet based upon a concrete biological hypothesis supported and improved by scientific trials. It is not a weight-loss diet. FODMAP stands for Fermentable Oligo- Di- and Mono- Saccharides And Polyols. Catchy, right? But the concept is simple—FODMAPs are short-chain sugars that we know most people digest poorly (meaning bacteria digest them), and you avoid FODMAPs on the FODMAP diet. (For the biochemists, that means avoiding fructans (oligosaccharide), lactose (disaccharide), fructose (monosaccharide), and all sugar alcohols such sorbitol (polyols).)

Many other diets have questionable scientific bases and are profit driven. The Atkins Diet was published by a cardiologist who never published any peer-reviewed work, but several books. The Paleo Diet was published by an “exercise scientist untrained in paleobiology”. This is not to say that these diets cannot be beneficial in any way. But they have not been tested and refined in the way the FODMAP diet has been, and their fundamental science is hazier. Putting the cart before the horse, they have been developed first for profit, and then researched afterwards, often with mixed results. To be fair, the scientific process is slow and contentious and doesn’t always lend itself well to studies as broad and complex as diet. But FODMAP was developed, tested, and improved using the scientific process. If you’re skeptical of diets, as I am, you can read up and convince yourself that this diet has a reasonable basis and good results.

What’s a FODMAP diet like?

If you are considering a FODMAP diet, you will have to do some research, and be able to prepare food often from scratch. The internet is a phenomenal tool, and there are even some dieticians you can consult online. FODMAP sensitivity is not the same thing as an allergy. You don’t have to absolutely eliminate FODMAP foods, you simply must aim to minimize them for a period of time.

To follow the FODMAP diet, you avoid FODMAP-laden foods for two weeks to two months (different sources vary in their recommendations, and provide rationales). After this time, you re-introduce foods in a controlled manner to identify trigger foods. Most IBS-sufferers are not sensitive to all FODMAPs. Many people report benefits within a few days of starting the diet, and 70% of IBS patients in peer-reviewed studies reported improvements following the diet. I personally had much less bloating within a few days. Following a FODMAP diet revealed that some of my symptoms are due to gastritis, which I’m now treating. I see now that I’ve had gastritis symptoms for a while, but I was unable to separate various gastrointestinal symptoms before this diet. I remain on the full FODMAP diet after three months, but I have eliminated one side issue.

What foods are and aren’t allowed?

Following the most basic level of the FODMAP diet, one avoids all garlic, onion, and gluten-containing foods. It is not a gluten-free diet, but grains containing gluten overlap almost perfectly with grains containing the FODMAP fructan. Beer happily is the major exception; it is FODMAP-free due to the fermentation process.

I consider the FODMAP approach an alternative way of categorizing foods. There is a common perception that vegetables and fruit are healthful, and grains and meat are less healthful. At least from the perspective of IBS, that is not a useful framework. On the FODMAP diet, meats are okay. Roughly half of grains, dairy, vegetables and fruit contain FODMAPs, and these are avoided on the diet. Specifically, greens and squash are okay, but broccoli, leeks, and  brussels sprouts aren’t. Citrus and melon are okay, but peaches, cherries, and figs aren’t. Lactose-free milk and hard cheeses are okay, and ice cream, fresh cheeses, and sour cream aren’t.

For those considering the diet, this is my favorite exhaustive list of allowed and disallowed foods.

TL;DR

In short, the FODMAP diet requires research and it’s a pain to follow, but it offers real promise to the numerous people suffering from IBS. If you’re considering the diet yourself, good luck. I hope this provided a better explanation of the topic than the sources I encountered when trying to understand this diet. To others, maybe this will help explain why your friend has such a fiddly diet, and why you should support them.

Food and science: Our international food

Leave a reply

The food we eat today may have been grown on the farm next door or in Chile or in Ethiopia. But thousands of years ago, their ancestors grew wild somewhere. The plants we eat originate from around the world.

Before recently reading Jared Diamond’s Guns, Germs, and Steel, I never appreciated the difficulty of the domestication of plants. Only a handful of plants comprise the majority of our crop production and calorie consumption. Even in thousands of years, many plants have never been domesticated. A domestic plant is a precious thing; without domestic plants, civilization would probably not have arisen.

Scientists can determine the likely wild origins of crop foods by the location of genetically similar wild plants. Tomatoes, potatoes, corn, chocolate, and chile peppers all come from the Americas. Sugar cane comes from India and New Guinea. Rice and soybeans are from China. Onions are from present-day Iran. Cashews are from Brazil.

Pecans are from the Mississippi valley, but they were not grown commercially until the 1880s! Macadamia nuts were the sole domesticated food from Australia, and they were not grown commercially until the 1880s either.

Although these plants come from around the world, you wouldn’t know it from our cuisines and cultures today. Italian food and tomato sauce, the Irish Potato famine, cashews and pineapples and chiles in Thai fried-rice, Belgian chocolate… Although humans have trouble domesticating plants, we are good at adopting them. In antiquity, similar adoptions happened with wheat and rice and millet. For discussion of how various plants influenced history, I recommend the book Fifty Plants that Changed the Course of History by Bill Laws.

It piques my curiosity– 200 years ago, pecans and macadamia nuts were wild. 500 years ago, most of the world didn’t know chocolate or potatoes or tomatoes. With modern science, what will be a dietary staple in 100 years?

Food and science: Why are peppers hot?

Leave a reply

Chili peppers, such as jalapeños and serranos and habañeros, are hot because they contain a chemical called capsaicin, which is an irritant to humans.

Why capsaicin?

If it is advantageous to plants to spread their seeds, why do the fruits (peppers) contain a chemical that repels animals? It turns out that birds are not sensitive to the effects of capsaicin. Thus, capsaicin repels animals whose chewing action may destroy the seed while not repelling birds. Additionally, capsaicin may function as a antifungal.

What does capsaicin do, chemically?

Capsaicin binds to receptors for heat and pain called vanilloid receptors. Capsaicin causes the receptor’s neuron to fire, which normally occurs at higher temperatures; thus, the brain interprets this neuron signal as sensing heat.

Capsaicin is just one kind of vanilloid compound; vanilla is another member of the vanilloid family, with a similar structure, but it does not act on vanilloid receptors. Now I wonder if peppers taste at all like vanilla to birds. A mystery for the ages.

Capsaicin in peppers

As you may have noticed, some peppers are hotter than others. This is because some contain more capsaicin and related chemicals than others. The relative hotness of peppers is measured by the Scoville scale. According to this scale, habañeros are a few times hotter than ají peppers which are a few times hotter than chipotle peppers. Bell peppers actually don’t contain capsaicin due to a recessive trait.

Contrary to what I learned growing up, the seeds don’t contain capsaicin. However, the pith that surrounds the seeds has the highest concentration. This may be why the hottest peppers look like wrinkly sphinx cats; they are just packed with pith (such as the Carolina Reaper pepper, bottom). You can reduce the hotness of a pepper for cooking by preferentially removing the white spines, which is the pith.

Habañero peppers have a Scoville rating of roughly 500,000. Pure capsaicin has a rating of 16 million. Some chemical called resiniferatoxin found in Moroccan cacti has a rating of 16 billion (1,000 times higher!). 40 grams of the stuff can kill a person.

So, there’s your overview of peppers for this Friday. Don’t consider this a challenge to go find that Moroccan cactus, but when your lips tingle after eating salsa, perhaps think of capsaicin.

Carolina reaper peppers, one of the hottest according to the Scoville Scale. Just look at the wrinkles! (Wikipedia)

Food and Science: Caramelization and the Maillard Reaction

1 Reply

When we cook food, we want it to be as flavorful as possible. Two types of chemical reactions contribute to browning; both of these reactions create hundreds or thousands of other molecules, which then add aroma and flavor. The higher temperature reaction you may be familiar with: caramelization is the breakdown and reaction of sugars. The Maillard reaction occurs at slightly lower temperatures (still usually above the boiling point of water); this reaction occurs between the amino acids of proteins and sugars.

Both of these reactions are so complex that scientists don’t know everything that occurs during them. We understand the basic nature of each reaction, but any plant or animal food contains literally thousands of different molecules that can all react together. Fortunately, we can still implement the process without a full understanding (and we have been for millennia), and a lot of very nice foods undergo either or both reactions.

The Maillard reaction and caramelization often occur at the same time, and produce similar results visually, so they can be tough to separate. If something contains both proteins and sugars, both reactions can occur with heat. Fortunately, they both taste good. They’re also easy to do at home. If you want to brown your food, get a skillet nice and hot. Make sure you’ve patted the food dry (this allows the surface to get hotter than the boiling point of water, thus allowing the reactions to occur), and sear away.

Food and science: understanding and cheating lactose intolerance

Leave a reply

A person is lactose intolerant when they no longer makes sufficient quantities of the enzyme lactase. Because the enzyme no longer breaks the lactose sugar down, bacteria in the large intestine do instead. The bacteria release a lot of gas when they do this, which irritates the large intestine and causes the symptoms we observe. 

Below is a quick run down to understanding lactose content in foods, and what I’ve done to continue eating awesome dairy food despite my own very inconvenient sensitivity.

What contains lactose?

As a short answer, more than you would think. Obviously ice cream and milk do. Hard cheeses contain very little. I often read that yogurt is well-tolerated by lactose-intolerants due to the bacterial culture, but I do not tolerate yogurt. Sour cream made by traditional methods is low in lactose, but many manufacturers add milk solids.

It gets more complicated. Many foods contain milk powder or whey. Milk powder is 50% lactose by weight, and whey is 10%-70% lactose. Pastries, hot chocolate mixes, pudding mixes, and even Doritos can contain milk powder and whey. Most annoyingly, products do not list the quantity of lactose contained.

Fortunately, several websites tabulate the lactose content of various foods (at least dairy– if you find one for prepared foods, I would love to hear about it). Steve Carper’s Super Guide to Dairy gives a great explanation of the lactose content of a wide variety of dairy products. This link has a decent list.

Circumventing lactose intolerance

Thanks to modern science, we can synthesize the lactase enzyme. The enzyme can be taken as pills and eaten with food, or added to the food as a liquid. I used to take the pills, but as my symptoms progressed, that method became insufficient. The stomach is a mixing chamber, and mixing is imperfect, so enough lactose still got through to cause issues.

After going a year without ice cream or yogurt, I decided to investigate my options. Online, I found the lactase liquid drops, which can be added to any liquid. In 24 hours, these drops reduce the lactose content of a product roughly 70%. I usually add more than the recommended quantity and wait three days to be extra sure. (A side note: I read in the amazon comments that some batches of the enzyme didn’t work; you can test the enzyme’s effectiveness using diabetic glucose test strips. Lactose splits into glucose and galactose, but food doesn’t normally contain glucose; a test strip indicating its presence in a treated food means the enzyme worked. I bought my enzyme in August, and did the test because heat can de-activate enzymes; it was super easy.)

Then I made lactose-free yogurt. I made lactose-free fresh mozzarella cheese (although I wasn’t very good at it). I bought an ice cream maker and made ice cream in any flavor I wanted. I made chocolate mousse. For Thanksgiving, I made ice cream and pumpkin pie with sweetened condense milk and mashed potatoes with sour cream.

Basically, you can add the enzyme to the cream or starting dairy product, let it be for a couple of days, and then cook as you normally would. In milk, the treatment slightly changes the flavor of the milk (it becomes a little cloying, because glucose tastes different than lactose), but in prepared foods I can’t tell the difference. Below are a couple pics of some projects I enjoyed very much. Hopefully this brief run down helps a few of you, or a least gives a picture of our complicated food science lives.

photo1

Green tea ice cream, made with matcha green tea.

photo2

Chocolate mousse.

 

Food and science: sous vide or water bath cooking

Leave a reply

In sous vide cooking, food is cooked in a water-bath at low temperatures (130-150 F) for longer times. Food cooked sous vide can be radically different in texture and taste than food cooked by more traditional methods. Even better, sous vide cooking is really, really easy.

What is sous vide?

In sous vide cooking, food in plastic bags is placed in a fixed-temperature water bath. The water bath temperature is held most easily by a digital controller. Some people build their own systems on the cheap. I bought this one, which in my opinion is worth every bit of $200.

As I discussed last week, bacteria die above 125 F. Consequently, food can be cooked at any temperature above 125 F (the closer to 125 F, the longer required for sanitation). This means a steak can be cooked to 130 F and be rare throughout, but also safe. For a 1 inch thick steak, this takes about an hour.

Why is it different?

Like a crock pot, sous vide cooking can be used to make tough cuts of meat extremely tender. Unlike a crock pot, the user has precise control over the set temperature, and the food is isolated from the water in which it cooks. This means that sous vide food isn’t soggy like slow cooker food so often is.

When we cook meat, the textural and color changes we observe are due to changes in the protein of the meat. Different proteins break down at different temperatures. The controller I use (linked above) allows control down to 0.1 C or 0.5 F. With such fine control, the cook can choose the exact temperature at which they wish to cook, and thus the effect they’d like to have on the protein. Poached eggs best demonstrate the results of this control. The proteins in the yolk coagulate at lower temperatures than the proteins in the white. By changing the cooking temperature only slightly, the cook can dramatically change the textures in the poached egg. This is called the perfect egg–at the link you can see eggs cooked to a variety of temperatures.

The set-up

For my set-up, the only major cost was the controller. I clamp it to the edge of a 8 qt pot (bigger would be better, but it’s what I had). Many people vacuum-seal their food before cooking, but the sealing system is an additional cost. I put my food in ziplock bags (glad bags are reported to be BPA-free). Then I add a little oil, squeeze the air out, and seal. To start cooking, I wait for the water in the pot to heat up and I clip the bag to the edge of the pot with a clothes pin.

Recipes and further reading

  • Citizen sous vide: an excellent general guide, with links to recipes and product reviews. Recipes are sorted by meat and cut.
  • Douglas Baldwin’s A Practical Guide to Sous Vide: a more technical discussion of sous vide with straightforward and instructive videos. This guide really explains the motivations of cooking sous vide.
  • Recipe for tri-tip steak: this recipe suggests cooking a tri-tip at 130 F for 6 hours, results shown below. You can see the meat is still pink in the middle. Cooking for six hours allowed it to tenderize, and all I had to do was cut up some meat and stick it in a bag. Very easy and delicious.

  • Tri-tip steak cooked sous vide.

    Tri-tip steak cooked sous vide.

Food and science: when is food safe?

1 Reply

The milk we get at the store is pasteurized, and we all know that chicken must reach 165 F and pork must reach 145 F. What is the source of these numbers, and what is their purpose?

Raw foods like meat and dairy contain a certain number of pathogens that can make us sick. These pathogens die when heated above about 125 F. So why are cooking temperatures much higher than 125 F? The recommended cooking temperatures are the temperatures your food must reach in order for a large enough portion of the bacteria to die nearly instantaneously. At 140 F, the salmonella in ground beef is reduced by a factor of ten every 5.48 minutes. Salmonella must be reduced by a factor of ten million to one, so you would have to hold this temperature for a while. At 150 F, the salmonella is reduced by a factor of ten every 0.55 minutes, so this is quite a bit faster. At 160 F, the bacteria reduces fast enough that by the time you’ve measured it, enough time has passed. The process of “sous vide” cooking uses lower temperatures applied steadily for long times to cook food. I will discuss this excellent cooking method in a future post.

The process of making food safe by reducing the bacteria is called pasteurization, which you may be more familiar with from the dairy aisle than meat, but the concept is the same. Also in dairy, the time for pasteurization depends upon the temperature. Pasteurized milk is heated to 162 F for at least 15 seconds while ultra-pasteurized milk is heated to 280 F for 1-2 seconds. Eggs are not usually pasteurized, but they can be when heated to 130 F for about an hour.

Douglas Baldwin’s section on food safety in his online guide to sous vide is the source of much of the information I present here. It is full of scientific citations, but is very readable, and I highly recommend it as further reading. Happy Valentine’s Day!