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By Zulfikar Abbany
Bread has been a source of basic nutrition for centuries, the holy trinity being wheat, maize and rice. It has also been the reason for a lot of innovation in science and technology, from millstones to microbiological investigations into a family of single-cell fungi called Saccharomyces.
There are breads of all shapes and sizes the world over — from flats and soda breads to buns, baguettes and boules, tinned loaves, crackers, plaits and sticks, baked with a griddle, in a Dutch oven or on a stone.
Jewish communities eat unleavened bread, or "matzo," at the Passover. It's flour and water, mixed and baked in under 20 minutes to prevent the dough from fermenting.
Ancient Greeks also made unleavened breads until about the last century BC, when leavens were introduced, and wheat flour replaced barley meal.
Asian chapatis and rotis and other Middle Eastern flatbreads, such as an Egyptian "aiysh," Palestinian "shrak," Syrian "aiysh shami" or Turkish "pide" are variations of the same, often wholemeal, bread that's used for scooping up saucy food. Some use leaven; others do just fine without. They are fast-action, practical breads.
If you like a little heft in your loaf, you will need a leavening agent.
For those short on time, you can use baking soda. That's a chemical compound of sodium bicarbonate mixed with potassium bitartrate, or cream of tartar.
Soda breads have their traditions in parts of eastern and central Europe, and in Ireland and Scotland, with Melrose loaves and "farls."
They can taste a bit bland, though, and are often considered only as an emergency solution on Sundays. No disrespect intended: They taste just fine fresh from the oven.
Whether it's chemical or more "natural," leavening relies largely on the production of carbon dioxide.
When you mix an acid, such as vinegar, buttermilk, yogurt or apple cider, with an alkaline compound like baking soda, you get CO2. That CO2 creates bubbles, which in turn capture steam in the oven and allow a bread to rise.
But it's better with yeast. Tastes better, too. It just takes more time.
What is yeast?
There are yeasts all around us — on grains, in the air, in biofuels. It even lives inside us, but that's not always a good thing.
Candida yeast can cause infections of the skin, feet, mouth, penis or vagina if it builds up too much in the body.
One of the most common yeasts, however, is Saccharomyces cerevisiae. That's "brewer's" or "baker's" yeast.
You can get fresh baker's yeast, often in 42-gram (1.48-ounce) cubes, or as dried yeast (quick action or active, which requires rehydration) in a sachet of 7 grams.
There's little difference: One is compressed and the other is dehydrated and granulated. But they do the same thing, essentially.
Some commercial yeast producers add molasses and other nutrients. But natural yeast has plenty of useful nutrients in it anyway, including B group vitamins, so who knows whether it's good or necessary to add them.
How does yeast work?
When you mix flour, yeast and water, you set off a veritable chain reaction. Enzymes in the wheat convert starch into sugar. And the yeast creates enzymes of its own to convert those sugars into a form it can absorb.
The yeast "feeds" on the sugars to create carbon dioxide and alcohol. The yeast burps and farts, releasing gases into the mix, and that creates bubbles to trap CO2.
It's a vital fermentation process that breaks down the gluten in the flour and helps make your bread more digestible.
The yeast cells split and reproduce, generating lactic and carbonic acid, raising the temperature and ultimately adding flavor to the mix.
The longer you leave the yeast to do its thing, the better for your bread. Time is more important than the amount of yeast.
In fact, that's an enduring question — how much yeast? I'll use 20 grams fresh yeast for 500 grams of flour. Others say that's enough yeast for 1 kilo. If you are converting a dry-yeast recipe to fresh yeast, some bakers advise tripling the weight. So, if a sachet of dried yeast is 7 grams, your fresh yeast is 21 grams.
But that also depends on the flours you are using, temperatures in the bowl and the room, and a host of other things. You'll just have to experiment and see. No number of books (and I've read a stack on bread) will help as much as trial and error.
There is one simple fact, though, and that is that more yeast does not make better bread. It might make it rise quicker and higher, but size isn't everything, right?
Oh, mind how and when you add salt. Salt slows the action in yeast. It toughens the gluten "network," or structure of your dough, making it tougher to knead or stretch.
Keep an eye on ambient temperatures as well. Yeast needs warmth to activate and react, but too much heat will kill it — that's basically what happens when you pop your loaf in the oven. You "finish" the process.
Wild yeast: Sourdough
So, good bread needs time. If you have a lot of time, why not move it up a notch and grow wild yeast — a sourdough starter — in your own home?
A sourdough starter is not to be mistaken (as it often is) for the leaven, or "mother," "sponge," or levain. That's more a second stage, a descendant of the starter. You take a scoop from your starter and add it to another flour and water mixture when you prepare the dough for a new loaf.
The sourdough process utilizes yeasts naturally present in flour and … yet more time. A longer fermentation process allows a richer lactic acid bacteria lactobacilli or LAB to evolve, and that can be healthy for your gut microbiome.
It's simple enough to start a sourdough starter. All you need is flour, warm water and time.
Some suggest equal measures of whole-grain flour and water at 28 degrees Celsius (82 degrees Fahrenheit), some say room temperature — just don't let the water exceed 40 C or the yeasts will die. Some suggest two parts flour to three parts water. But it's up to you whether you want a drier or wetter starter. You will know only through experimentation.
Some say you should filter tap water to remove chemicals like fluoride and avoid using water that's boiled and then cooled. Others say that really doesn't matter.
The main thing is, keep it clean and give it time. Days, weeks, months and years.
In the first week, discard half of the mixture each day and add a fresh batch of flour and water. You can use the discarded starter to make patties or a truly dark Russian black bread. But that's for later.
Make sure the starter can breathe — don't screw on a lid, use a cloth to cover it. And after a week, you should start to see bubbles. That's when you know your starter alive and active.
The tricky thing now is keeping it alive and the right amount of active whenever you need some for a loaf. After over a year of cultivating a starter, I still can't get it right.
You have to feed your starter regularly with fresh flour and water. If it develops a watery alcohol on top, that's "hooch," a protective layer and just means your starter needs refreshing. If you've only got time to feed it once a week, slow the process by chilling it in a fridge.
Sourdough takes dedication and a scientific approach. You can't knock out a boule.
Yeast aside, it's important to allow time for your flour and water to "autolyze." If you add salt too soon, you will inhibit the gluten structure. Give it time, and two proteins in the wheat, gliadin and glutenin, will bond to give you that all-important gluten (apologies to the gluten-intolerant), the gluten will give the yeast more feed, and you will have an airy, nutritious bread at the end.
But all too often I get impatient and end up having to "juice" my sourdough with a pinch of fresh yeast. It still has that distinctive, sour taste, but it's not "pure." I won't give up. One day I'll make a perfect sourdough rye.
Reposted with permission from DW.
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EcoWatch Daily Newsletter
Farmers are the stewards of our planet's precious soil, one of the least understood and untapped defenses against climate change. Because of its massive potential to store carbon and foundational role in growing our food supply, soil makes farming a solution for both climate change and food security.
Soil can act as a natural "carbon sink." Climate Central, 2019
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By Shelly Miller
The vast majority of SARS-CoV-2 transmission occurs indoors, most of it from the inhalation of airborne particles that contain the coronavirus. The best way to prevent the virus from spreading in a home or business would be to simply keep infected people away. But this is hard to do when an estimated 40% of cases are asymptomatic and asymptomatic people can still spread the coronavirus to others.
It’s All About Fresh, Outside Air<p>The safest indoor space is one that constantly has lots of <a href="https://www.epa.gov/indoor-air-quality-iaq/how-does-outdoor-air-enter-building" target="_blank">outside air</a> replacing the stale air inside.</p><p>In commercial buildings, <a href="https://www.ncbi.nlm.nih.gov/books/NBK143277/" target="_blank">outside air is usually pumped in</a> through heating, ventilating and air-conditioning (HVAC) systems. In <a href="https://www.epa.gov/indoor-air-quality-iaq/how-does-outdoor-air-enter-building" target="_blank">homes, outside air gets in</a> through open windows and doors, in addition to seeping in through various nooks and crannies.</p><p>Simply put, the more fresh, outside air inside a building, the better. Bringing in this air dilutes any contaminant in a building, whether a virus or a something else, and <a href="https://doi.org/10.1111/j.1600-0668.2010.00703.x" target="_blank">reduces the exposure of anyone inside</a>. Environmental engineers like me quantify how much outside air is getting into a building using a measure called the <a href="https://doi.org/10.1038/jes.2013.30" target="_blank">air exchange rate</a>. This number quantifies the number of times the air inside a building gets replaced with air from outside in an hour.</p><p>While the exact rate depends on the number of people and size of the room, most experts consider roughly <a href="https://doi.org/10.1034/j.1600-0668.2002.01145.x" target="_blank">six air changes an hour</a> to be good for a 10-foot-by-10-foot room with three to four people in it. In a pandemic this should be higher, with one study from 2016 suggesting that an exchange rate of nine times per hour <a href="https://doi.org/10.1177%2F1420326X16631596" target="_blank">reduced the spread of SARS, MERS and H1N1</a> in a Hong Kong hospital.</p><p>Many buildings in the U.S., <a href="https://doi.org/10.1111/ina.12403" target="_blank">especially schools</a>, do not meet recommended ventilation rates. Thankfully, it can be pretty easy to get more outside air into a building. Keeping <a href="https://doi.org/10.1016/S0960-1481(99)00012-9" target="_blank">windows and doors open</a> is a good start. Putting a box fan in a window blowing out can greatly increase air exchange too. In buildings that don't have operable windows, you can change the mechanical ventilation system to increase how much air it is pumping. But in any room, the more people inside, the faster the air should be replaced.</p>
Using CO2 to Measure Air Circulation<p>So how do you know if the room you're in has enough air exchange? It's actually a pretty hard number to calculate. But there's an easy-to-measure proxy that can help. Every time you exhale, you <a href="https://doi.org/10.1111/ina.12383" target="_blank">release CO2</a> into the air. Since the coronavirus is most often spread by breathing, coughing or talking, you can use <a href="https://pdfs.semanticscholar.org/dd7e/b2870c38f70e5285e5118ed6f158c091f7cf.pdf" target="_blank">CO2 levels</a> to see if the room is filling up with potentially infectious exhalations. The CO2 level lets you estimate if enough fresh outside air is getting in.</p><p>Outdoors, CO2 levels are just above 400 parts per million (ppm). A well ventilated room will have around <a href="https://doi.org/10.1111/j.1600-0668.1999.00003.x" target="_blank">800 ppm of CO2</a>. Any higher than that and it is a sign the room might need more ventilation.</p><p>Last year, researchers in Taiwan reported on the <a href="https://doi.org/10.1111/ina.12639" target="_blank">effect of ventilation on a tuberculosis outbreak</a> at Taipei University. Many of the rooms in the school were underventilated and had CO2 levels above 3,000 ppm. When engineers improved air circulation and got CO2 levels under 600 ppm, <a href="https://doi.org/10.1111/ina.12639" target="_blank">the outbreak completely stopped</a>. According to the research, the increase in ventilation was responsible for 97% of the decrease in transmission.</p><p>Since the coronavirus is spread through the air, higher CO2 levels in a room likely mean there is a <a href="https://doi.org/10.1111/ina.12639" target="_blank">higher chance of transmission</a> if an infected person is inside. Based on the study above, I recommend trying to keep the CO2 levels below 600 ppm. You can buy <a href="https://doi.org/10.5194/amt-7-3325-2014" target="_blank">good CO2 meters</a> for around $100 online; just make sure that they are accurate to within 50 ppm.</p>
Air Cleaners<p>If you are in a room that can't get enough outside air for dilution, consider an air cleaner, also commonly called air purifiers. These machines remove particles from the air, usually using <a href="https://doi.org/10.1016/j.cap.2005.07.013" target="_blank">a filter</a> made of tightly woven fibers. They can <a href="https://shellym80304.files.wordpress.com/2020/06/miller-leiden-et-al-1996.pdf" target="_blank">capture particles containing bacteria and viruses</a> and can help reduce disease transmission.</p><p>The U.S. Environmental Protection Agency says that <a href="https://www.epa.gov/coronavirus/air-cleaners-hvac-filters-and-coronavirus-covid-19" target="_blank">air cleaners can do this for the coronavirus</a>, but not all air cleaners are equal. Before you go out and buy one, there are few things to keep in mind.</p><p>The first thing to consider is <a href="https://shellym80304.files.wordpress.com/2020/06/air-cleaner-report.pdf" target="_blank">how effective an air cleaner's filter is</a>. Your best option is a cleaner that uses a high-efficiency particulate air (<a href="https://doi.org/10.1016/S0021-8502(05)80214-9" target="_blank">HEPA</a>) filter, as these remove more than <a href="https://doi.org/10.1063/1.2771421" target="_blank">99.97% of all particle sizes</a>.</p><p>The second thing to consider is how powerful the cleaner is. The bigger the room – or the more people in it – the more air needs to be cleaned. I worked with some colleagues at Harvard to put together a tool to help teachers and schools determine <a href="https://docs.google.com/spreadsheets/d/1NEhk1IEdbEi_b3wa6gI_zNs8uBJjlSS-86d4b7bW098/edit#gid=1275403500" target="_blank">how powerful of an air cleaner you need for different classroom sizes</a>.</p><p>The last thing to consider is the validity of the claims made by the company producing the air cleaner.</p><p>The Association of Home Appliance Manufacturers certifies air cleaners, so the AHAM Verifide seal is a good place to start. Additionally, the California Air Resources Board has a <a href="https://ww2.arb.ca.gov/our-work/programs/air-cleaners-ozone-products/california-certified-air-cleaning-devices" target="_blank">list of air cleaners</a> that are certified as safe and effective, though not all of them use HEPA filters.</p>
Keep Air Fresh or Get Outside<p>Both the <a href="https://www.who.int/news-room/commentaries/detail/transmission-of-sars-cov-2-implications-for-infection-prevention-precautions" target="_blank">World Health Organization</a> and <a href="https://www.cdc.gov/coronavirus/2019-ncov/daily-life-coping/deciding-to-go-out.html" target="_blank">U.S. Centers for Disease Control and Prevention</a> say that poor ventilation increases the risk of transmitting the coronavirus.</p><p>If you are in control of your indoor environment, make sure you are getting enough fresh air from outside circulating into the building. A CO2 monitor can help give you a clue if there is enough ventilation, and if CO2 levels start going up, open some windows and <a href="https://www.advisory.com/daily-briefing/2020/07/17/outdoor-gathering" target="_blank">take a break outside</a>. If you can't get enough fresh air into a room, an air cleaner might be a good idea. If you do get an air cleaner, be aware that they don't remove CO2, so even though the air might be safer, CO2 levels could still be high in the room.</p><p>If you walk into a building and it feels hot, stuffy and crowded, chances are that there is not enough ventilation. Turn around and leave.</p><p>By paying attention to air circulation and filtration, improving them where you can and staying away from places where you can't, you can add another powerful tool to your anti-coronavirus toolkit.</p>
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The tiny island nation of Mauritius, known for its turquoise waters, vibrant corals and diverse ecosystem, is in the midst of an environmental catastrophe after a Japanese cargo ship struck a reef off the country's coast two weeks ago. That ship, which is still intact, has since leaked more than 1,000 metric tons of oil into the Indian Ocean. Now, a greater threat looms, as a growing crack in the ship's hull might cause the ship to split in two and release the rest of the ship's oil into the water, NPR reported.
On Friday, Prime Minister Pravind Jugnauth declared a state of environmental emergency.
France has sent a military aircraft carrying pollution control equipment from the nearby island of Reunion to help mitigate the disaster. Additionally, Japan has sent a six-member team to assist as well, the BBC reported.
The teams are working to pump out the remaining oil from the ship, which was believed to be carrying 4,000 metric tons of fuel.
"We are expecting the worst," Mauritian Wildlife Foundation manager Jean Hugues Gardenne said on Monday, The Weather Channel reported. "The ship is showing really big, big cracks. We believe it will break into two at any time, at the maximum within two days. So much oil remains in the ship, so the disaster could become much worse. It's important to remove as much oil as possible. Helicopters are taking out the fuel little by little, ton by ton."
Sunil Dowarkasing, a former strategist for Greenpeace International and former member of parliament in Mauritius, told CNN that the ship contains three oil tanks. The one that ruptured has stopped leaking oil, giving disaster crews time to use a tanker and salvage teams to remove oil from the other two tanks before the ship splits.
By the end of Tuesday, the crew had removed over 1,000 metric tons of oil from the ship, NPR reported, leaving about 1,800 metric tons of oil and diesel, according to the company that owns the ship. So far the frantic efforts are paying off. Earlier today, a local police chief told BBC that there were still 700 metric tons aboard the ship.
The oil spill has already killed marine animals and turned the turquoise water black. It's also threatening the long-term viability of the country's coral reefs, lagoons and shoreline, NBC News reported.
"We are starting to see dead fish. We are starting to see animals like crabs covered in oil, we are starting to see seabirds covered in oil, including some which could not be rescued," said Vikash Tatayah, conservation director at Mauritius Wildlife Foundation, according to The Weather Channel.
While the Mauritian authorities have asked residents to leave the clean-up to officials, locals have organized to help.
"People have realized that they need to take things into their hands. We are here to protect our fauna and flora," environmental activist Ashok Subron said in an AFP story.
Reuters reported that sugar cane leaves, plastic bottles and human hair donated by locals are being sewn into makeshift booms.
Human hair absorbs oil, but not water, so scientists have long suggested it as a material to contain oil spills, Gizmodo reported. Mauritians are currently collecting as much human hair as possible to contribute to the booms, which consist of tubes and nets that float on the water to trap the oil.
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Environmentalists and ornithologists found a friend in a federal court on Tuesday when a judge struck down a Trump administration attempt to allow polluters to kill birds without repercussions through rewriting the Migratory Treaty Bird Act (MBTA).
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