There are some things we don’t need scientists to tell us — like the fact that cheese is delicious and was created by the dairy gods to please us — but there are other questions we need answered by the professionals in order to live our best lives. Like what the ideal kind of cheese is for a perfectly gooey, melty grilled cheese. Here comes the science! 
 
 A three-minute video from the series Reactions, hosted by the American Chemical Society, delves into the science of how cheese melts: it all comes down to how casein proteins clump together into spheres called micelles, which are held together by calcium and are full of fat. The surface of a micelle is negatively charged, so usually the little balls would bounce away from each other. 
 
 But when lactic acid gets involved, the micelles smack into each other and create chains that trap water and turn into a mess of cheesy goo. Cheeses that age longer contain more lactic acid, lowering its PH. That means sharper cheeses have a lower pH than their counterparts, which don’t age as long. 
 
 According to the American Chemical Society’s video, what this all means is that the ideal pH level for a cheese used to make grilled cheese is perfectly balanced between 5.3 to 5.5 (here’s a list [PDF] of PH levels in food). Any lower and cheese will release all its oil when heated, leaving curdled, clumpy clusters. 
 
 So what should you choose? Try gouda, gruyére or manchego. If you’re choosing between mild and sharp cheddar, go with mild — it has the texture you want, and won’t break down like its sharp counterpart. 
 
 If you want suggestions on how to cook that grilled cheese once you’ve selected which variety you want, check out our somewhat scientific We Tried It investigation. 
 
 For more science and cheese and cheese science, check out the video below: ||||| Published on Nov 3, 2015 
 
 This week Reactions is taking a look at some cheesy chemistry in the form of a sandwich. We're giving you some science based tips on how to make the perfect grilled cheese sandwich. Consider this a chemical ode to one of the finest comfort foods ever created, the grilled cheese sandwich. Cheese making is an incredibly complex chemical process, and at a certain point, you may have learned the hard way that some cheeses simply don't make the grill grade. Why is it that some cheeses melt perfectly while others crumble into a nasty, oily mess? Today we're going answer that question for you, and while we're at it, we wanted to offer you some scientific advice on how to optimize your ingredients for the perfect grilled cheese experience. 
 
 
 
 Go check out "The Kitchen As Laboratory," a fantastic book about science and cooking, which inspired this episode: http://www.amazon.com/The-Kitchen-Lab... 
 
 
 
 
 
 Find us on all these places: 
 
 Subscribe! http://bit.ly/ACSReactions 
 
 Facebook! http://facebook.com/ACSReactions 
 
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 Music: 
 
 Pure Natural - Touch me 
 
 Sam Leopard - Soul 
 
 
 
 Writer/Producer: 
 
 Kirk Zamieroski 
 
 
 
 Executive Producer: 
 
 Adam Dylewski 
 
 
 
 Scientific consultants: 
 
 Jennifer Kimmel, Ph.D. 
 
 Darcy Gentleman, Ph.D. 
 
 Sophia Cai 
 
 
 
 Sources: 
 
 The Kitchen as Laboratory - http://www.amazon.com/The-Kitchen-Lab... 
 
 
 
 On Milk Proteins - http://www.milkfacts.info/Milk%20Comp... 
 
 
 
 Texture of Cheese - http://www.journalofdairyscience.org/... 
 
 
 
 On Processed, "American" Cheese - https://pubs.acs.org/cen/whatstuff/st... 
 
 
 
 FDA on standards on American Cheese - https://www.fsa.usda.gov/Internet/FSA... ||||| LISTEN TO ARTICLE 5:38 SHARE THIS ARTICLE Share Tweet Post Email 
 
 American cheese will never die. It has too many preservatives. 
 
 But it’s melting away. 
 
 One by one, America’s food outlets are abandoning the century-old American staple. In many cases, they’re replacing it with fancier cheeses. 
 
 Panera Four Cheese Grilled Cheese Source: Panera Bread 
 
 Wendy’s is offering asiago. A&W’s Canada locations switched to real cheddar. McDonald’s is selling the Big Mac’s soft, orange square of American cheese with a version that doesn’t contain artificial preservatives. Cracker Barrel ditched its old-fashioned grilled cheese. So did Panera Bread, replacing American with a four-cheese combo of fontina, cheddar, monteau and smoked gouda. The result: higher sales. 
 
 American cheese is “an ingredient we’re looking to less and less in our pantry,” said Sara Burnett, the chain’s director of wellness and food policy. 
 
 Cultural Crossroads 
 
 American (cheese) culture is at a crossroads. The product, made famous by the greatest generation, devoured by boomers on the go and touted as the basis for macaroni and cheese, the well-documented love object of Gen X, has met its match with millennials demanding nourishment from ingredients that are both recognizable and pronounceable. 
 
 Kraft Singles Photographer: Daniel Acker/Bloomberg 
 
 Don’t rely on anecdotal evidence. The data show it, too. U.S. sales of processed cheese, including brands like Kraft Singles and Velveeta, a mainstay of delicacies such as ballpark nachos, are projected to drop 1.6 percent this year, the fourth-straight year of declines, according to Euromonitor International. 
 
 The end of the affair is also evident at the Chicago Mercantile Exchange, where 500-pound barrels of cheddar -- which are used to make American cheese -- are selling at a record discount to 40-pound cheddar blocks, the cheddar that shows up on party platters. That’s because demand for the cheese in the barrels has been dwindling for years, according to Alyssa Badger, director of operations at Chicago-based HighGround Dairy. 
 
 American cheese isn’t the point of a lot of the barrel production, Badger said. It’s for the byproduct whey, a staple of pricey protein shakes. 
 
 Cheese Factories 
 
 Decline is also evident when looking at the manufacturing landscape. The number of U.S. cheese factories increased 40 percent between 2000 and 2017, but the growth is from small, specialty cheesemakers, said Matt Gould, editor at Dairy & Food Market Analyst Inc. 
 
 Prices at the grocery store for processed American cheese have been slipping, too, dipping below $4 a pound for the first time since 2011, according to the U.S. Bureau of Labor Statistics. 
 
 Gayle Voss, owner of Gayle V’s Best Ever Grilled Cheese in Chicago, takes two slices of fresh-baked sourdough and fills them not with American cheese but with Wisconsin-made butterkäse cheese. It’s made in small batches by farmers who know the names of their cows. It’s melty and slightly stretchy, and yes, buttery. It’s what people want these days, she said. 
 
 “I could buy preservative-filled cheese and butter,” Voss said. “But I’m all-out on supporting small businesses and offering a good, quality product, and the minute people bite into it, they know -- because it’s so good.” Pause here to imagine taking a bite of crunchy bread and melted cheese that forms a string as mouth and sandwich separate. “People want to know where their food is coming from,” she said, “and my sales reflect that.” 
 
 Voss said her husband will use Kraft Singles to whip up a quick sandwich for himself at home, something that cheeses her off. But it’s what he grew up with, she said. 
 
 Cheese Born 
 
 Most Americans did. American cheese was born at a time when utility reigned. James and Norman Kraft invented processed cheese in 1916 and sold it in tins to the U.S. military during World War I. Soldiers kept eating it when they returned home and its popularity soared. It wasn’t until 1950 that Kraft perfected the slicing. Soon after came a machine that could individually wrap the slices, and in 1965, Kraft Singles were born. 
 
 Like Wonder Bread, society marveled at the uniformity of the product, the neatness of the slices, the long shelf life and its ability to stay moist even in the desert, in the middle of the summer, at noon. 
 
 Ingredients include substances that sound like a chemistry set: sodium citrate, calcium phosphate, natamycin, modified food starch. And, of course, milk. 
 
 Kraft Singles 
 
 Though 40 percent of U.S. households buy Kraft Singles, overall sales are flat, according to Peter Cotter, general manager of cheese and dairy for Kraft Heinz Co. Kraft has a 30-person research-and-development team working on ways to get American cheese into more homes, he said, offering qualities that healthier, more natural cheeses can’t. For instance, “the melt.” 
 
 “Honestly, you can’t get that in a natural cheese,” Cotter said. “It’s a very unique product. The creamy smooth texture and melt of the cheese. The natural cheeses, they just don’t melt that way.” 
 
 The backlash to the backlash remains robust, with about $2.77 billion in retail sales this year, according to Euromonitor. Some trendy restaurants are going retro on their menus, hearkening back to somebody’s idea of what a classic America might’ve been like before fancy cheeses ruined the youth. After all, Homer Simpson pulled an all-nighter eating 64 slices of American cheese, not gouda, provolone or even butterkäse, which, after all, just means butter cheese in German. 
 
 Burger joint Mini Mott opened this summer in Chicago’s trendy Logan Square neighborhood and when diners order a cheeseburger they’ll get American cheese and nothing else. Chef Scott Sax said he buys it in five-pound bricks from a supplier in Minnesota. 
 
 “There’s nothing pure or organic about it,” Sax said. “The ingredients are very American.”
– Looking for the perfect cheese for the ultimately gooey, perfectly melted grilled cheese sandwich? Good news: Scientists with the American Chemical Society have put out a three-minute video from the society's "Reactions" series on YouTube all about that very subject. And the winners are ... gouda, gruyére, or manchego, with mild cheeses melting more beautifully than sharp. It's all about how casein proteins clump together (the resulting spheres are called micelles) when cheese melts. These micelles, which are held together by calcium and are gloriously fatty, are negatively charged, meaning those tiny balls bounce apart. Add lactic acid, however, which goes up the longer a cheese ages, and those micelles smack together, trapping water and getting all gooey, reports Consumerist. But wait, there's more. The older the cheese, the more lactic acid, which in turn lowers the cheese's pH—thus sharper cheeses have a lower pH and mild ones a higher pH. The ideal pH, in fact, is right between 5.3 and 5.5, with cheese of lower pH releasing their oils when heated and getting clumpy. This is why gouda, gruyére, or manchego are ideal but on the milder side; if they age too long and become sharper, the pH dips too low and the cheese breaks down more easily, meaning you could end up with a curdled mess while heating it. (Check out why this cheese tests best for pizza.)