This article was first published in The Montreal Gazette.

That’s the conclusion that some may draw from a Swedish study that sent the media into rapture, spewing out headlines about high-fat cheese preventing dementia. The study recently published in the journal Neurology found people who ate 50 grams or more of high-fat cheese daily for up to 25 years had a 13 per cent lower risk of dementia than those eating less than 15 grams. What we have here is yet another paper destined be tossed on the growing heap of nutritional studies that may have been properly carried out as far as methodology goes, but have essentially no practical significance.

First, the results barely reach statistical significance. Then there is the issue of the food frequency questionnaires being completed only once at the beginning of the trial with the assumption that diets would not be altered over the period of the study, which is unlikely. The most significant reductions in the risk of dementia were among subjects whose high cheese consumption paralleled a reduction in both processed and red meat intake, so any benefit may be due not to what they were eating but to what they were not eating.

Now getting back to that grilled cheese sandwich. I don’t think its 50-gram content of cheese is going to have an impact on the risk of dementia, especially given that daily consumption over decades is an unlikely scenario. Neither am I put off by the 10 grams of saturated fat in the cheese. Yes, saturated fat can raise LDL cholesterol, which is a risk factor for heart disease. However, a number of recent meta-analyses have not found clear evidence that higher total saturated fat intake is directly associated with greater risk of coronary heart disease or cardiovascular health. Furthermore, cheese consumption itself is not linked to higher cardiovascular disease, possibly because the fat is locked in a matrix of protein causing poorer absorption.

With the health concern now dealt with, we are left with the question of how to best prepare a grilled cheese sandwich. We want one that delivers a scrumptious taste with the cheese melted just right, and the bread properly toasted and not burned.

The classic cheeses used are cheddar or American processed cheese because these melt smoothly with no clumping of proteins. Cheese is composed mainly of fat trapped in a network of protein molecules held together by calcium ions. Some of these calcium bridges, as they are called, have to be broken for the cheese to melt. With the breaking of the bridges, the proteins become more independent and move about more easily as heat is applied. In their liberated form, the proteins also act as emulsifiers, attracted both to water and fat, preventing fat from oozing out of the cheese. However, if too many calcium bridges are broken, the freely moving proteins can get tangled and form a clump.

What determines how many of the calcium bridges are broken as heat is applied? The main factor is the number of such bridges that are found in the cheese to start with, which in turn depends on the cheese’s acidity. Acids leach out calcium and release the proteins. But as we saw, if too many proteins are released, you get lumps. It turns out that the ideal situation is a pH in the vicinity of 5.3 to 5.5, which is achieved by cheddaring. The cheddaring process involves the formation of curds by adding a mixture of enzymes found in calf stomach, known as “rennet,” to pasteurized milk. The curds are then infused with lactic acid-producing bacteria and compressed into blocks that are then stacked upon each other. During this cheddaring process, the lactic acid causes calcium to be released from the protein network allowing protein molecules to slide smoothly past each other when heated.

American cheese is made by “processing” cheddar cheese, although Colby and Monterey are sometimes also mixed with the cheddar. The “process” involves the addition of sodium citrate and or sodium phosphate to the cheese. The sodium ions replace calcium but do not have the same “gluing effect” as calcium. Although processed cheese is often denigrated by food snobs, the fact is that there is no nutritional difference between it and regular cheese. But there surely is a difference in taste.

Although many people are satisfied with the taste of melted cheddar or American cheese, you can add some zip to the taste with some Parmesan. This tasty cheese cannot be used solely in a grilled cheese sandwich because it turns crispy instead of melting. However, you can add some grated or very thinly sliced Parmesan to the cheddar inside the sandwich. Gruyère can also be combined with cheddar as a further gift to the taste buds.

Now for the bread. No, the common grocery store sliced white bread will not do. You have to hunt down a loaf of great sourdough. Coat the outside of the two slices with a little butter and then a layer of mayonnaise into which a bit of grated Parmesan is blended. The butter helps transfer heat to the bread and the mayo provides amino acids that can engage in the Maillard reaction with the naturally occurring sugars in the bread. It is this reaction that creates the desirable brown colour and yields the numerous flavour compounds associated with baked, seared and fried foods. The Parmesan in the mayo becomes crispy with heat, making for a delectable texture.

Temperature is important. It has to be high enough to drive the Maillard reaction and melt the cheese without burning the bread. For a stovetop setting this would be in the medium-low range. Place the sandwich in the warmed pan and flip once the underside is a golden brown, around three minutes. The second side should turn brown in a shorter time, maybe two minutes. Finally, the diagonal cut maximizes exposed surface area meaning that more volatile compounds reach the nose per bite, which the brain interprets as “better taste.”

Once you have made the sandwich, inspect it for any images that may appear on the toast. Back in 2004, a woman noted one that seemed to be of the Virgin Mary on a sandwich she had prepared. She managed to sell it on eBay for $28,000 to an online casino. My grilled cheese sandwiches have failed to produce any images and have only been profitable to the palate.

@‌JoeSchwarcz