Patties, especially in the USA, come in all different shapes and sizes (and cooking methods, which will be addressed in the next Theory Thursday!). At its inception less than 50 years ago, Big Macs were considered a huge burger (hence the moniker – apparently “The Aristocrat” wasn’t as well received), with 2 patties at under 50g each. Even one 50g patty was seen as large – many patties were around 1oz, or 28g (damn imperial units). Of course (as popularised by White Castle), customers tended to eat more than one of these smaller creations. Eating one larger burger is a much more recent invention, borne of cheaper, more accessible beef. In the USA, much like Australia, broadly speaking a burger in a pub will be a lot larger than a fast food burger, often about double the size (112g, or 4oz, is the size of the iconic “quarter pounder”; many pub burgers are 200g, because this is a convenient patty machine setting!).
They both have their pros and cons. We, burger idealists, wanted the best of both worlds: a patty the would cook reasonably quickly, having a good crust to inner meat ratio (as exemplified by thin fast food style patties), but also with some substance to them, so we could get that crust without totally overcooking the middle (as exemplified by thick pub style patties). Hence we arrived at 140g, for us the ideal compromise between the two. Its thickness still allows for easy consumption (the burger and eating in your car, often with one hand while driving, are inextricably linked historically), but it also isn’t so thin so as to disappear in the face of condiments, cheese, and other toppings.
It takes an awful amount of work to make sure our patties are consistently 140-142g, weighing them by hand. But it’s incredibly important to us that they are weighed by hand (as outlined previously, the less handling, the less protein crosslinking, and no machine can replicate the careful human hand), and it’s also incredibly important that they are consistent (within 1.5% in weight). The rationale for consistency is simple: it gives us the best chance at cooking our patties as close to our ideal final temperature as we can.