I’ve been working a bit on inflation and the highly problematic concept of the ‘cost of living’ (shorter JQ: what matters is the purchasing power of wages, not the cost of some basket of goods). As part of this, I’ve been looking at how particular prices have changed over time, focusing on basics like bread and milk.
One striking thing that I found out is that, until quite late in the 20th century, the standard loaf of bread used to calculate consumer price indexes in Australia weighed 4 pounds (nearly 2kg). That’s about as much as three standard loaves of sliced bread. Asking around, this turns out to be the largest of the standard sizes specified in legislation like the Western Australian Bread Act which was only repealed in 2004, AFAICT.
Going back a century or so further, the Speenhamland system of poor relief in England specified the weekly nutrition requirements of a labouring man as a ‘gallon loaf” of bread, made from a gallon (about 5 litres) of flour, and weighing 8.8 pounds (4kg). Bread was pretty much all that poor people got to eat, so the amount seems plausible.
But why one huge loaf rather than, say seven modern-size loaves? And turning that question around, why are our current loaves so much smaller?
I haven’t been able to find anything about this. Looking for images of these gallon loaves is difficult, because of the popularity of ‘loaf tanks’ made in the shape of bread loaves and with a capacity measured in (US) gallons.
Whenever I see a development like this, I think about shrinkflation, the process of reducing the size of a product as a surreptitious way of increasing the unit price. But shrinkflation is ultimately a cyclical process. When the standard size has been shrunk as far as it will go, it is replaced by a new ‘jumbo’ or ‘economy’ size, the same as the original standard size.
So, my best guess is that it is all to do with that proverbially marvellous invention, sliced bread. Sliced bread requires a standard size, and small is easier to handle. Also (guessing here), sliced bread may not keep as well, so we buy smaller loaves more frequently.
I’ve had some useful responses from Bluesky and Mastodon on this (I shudder to think how XTwitter would respond if I were still there), and now I’m throwing it over to my newsletter and blog readers. Any info would be appreciated.
John Quiggin 
70 years ago, my mother would buy half a loaf from the baker’s van which serviced our street every weekday. It wasn’t significantly bigger than half the loaves sold by places like Baker’s Delight today, so any shrinkflation took place a long time ago. And that was before sliced bread became a thing – indeed before supermarkets sold bread. Before supermarkets, now I think about it.
Perhaps the move to smaller loaves happened because bakeries selling fresh products every day became commonplace some time in the first half of the 20th century. And post-WW2 prosperity meant most people could afford to buy them. Why hack pieces off a big dry (possibly mouldy) week-old loaf when you can buy a fresh fragrant half loaf from the van passing the gate?
I agree that convenience in shopping is probably part of it, but I also suspect that baking techniques are part of it. Modern industrial bread is a very different beast than older styles. Flours are more highly processed and I would guess expectations of softness and density are different as well. Comparing a modern supermarket loaf of bread to a traditional mass produced loaf would likely demonstrate a whole range of differences.
On measuring the cost of living: “what matters is the purchasing power of wages, not the cost of some basket of goods”
If your wage is $100 and the price of the single basket you consume is $2 then you can buy 50 baskets. If the price goes to $4 then you can either say your purchasing power has declined by 1/2 or that the cost of the basket has doubled. I don’t understand the difference?
Can you please make your point more explicitly?
I think what John is saying is that it’s more important to measure how many “loaves of bread” your wage can purchase rather than the price of the loaf itself. And I agree. I think we should move to an outcomes based approach where we agree what constitutes a minimum or maybe a good standard of living that we should aspire for all Australians.
For instance, 50 years ago, someone with a high school education could purchase a home and raise a family on a single income. That’s no longer the case but the clearly manipulated CPI numbers would suggest otherwise.
That sounds like the real wage. The nominal wage deflated by a price index. Then if real wages increase the cost of living improves. I agree.