If you don't already know, bagged milk is just one of the many things that is associated with Canada.

While our neighbours to the south often find this pretty strange, people in Quebec, Ontario, and the maritime provinces are used to cutting the corner off of a pouch of milk and putting it in a reusable pitcher to drink from. 

Here's why some Canadians get their milk in a bag that contains three smaller pouches rather than jugs. 

Stunned by the size of these giant milk bags sold in supermarkets in #Canada! #milk #travel pic.twitter.com/HDVKVDicqo

— Carol C (@carolchan9394) September 22, 2017

In the 1970s, Canada converted to the metric system which meant dairy producers needed to adapt as well. However, it wasn't so easy to replace and resize the existing containers that milk was sold in, which were measured in imperial quarts. 

Replacing heavy glass bottles was too expensive for the milk industry as opposed to milk bags, which could be cheaply adjusted. A one-quart bag easily changed into a 1.3-litre bag, meaning three-quart bags of milk became four-litre bags in parts of the country. 

In some parts of Canada, milk comes in bags. 😂🤣 pic.twitter.com/6UbQdCKCsZ

— Jack Forge (@TheJackForge) September 10, 2020

In the 1980s, once Brian Mulroney's government relaxed rules on metric measurements and hard plastic became cheaper, the milk bag slowly lost traction in provinces like Alberta and B.C. 

In Ontario, regulations restricting the sale of more than one pint of milk in containers other than bags meant milk would still be sold this way. Although this was amended back in 2018, the milk bag has yet to go anywhere. 

Because some of you are not aware of this:

Bagged milk in Canada. Not available in all parts of the country now, but I salute those that still have it.

Three of the small bags come in the big bag, then we schfloomp it into the jug, snip off the corner, and pour! pic.twitter.com/TbTaS4VQID

— SassyMétisChick ❤️ 🇨🇦❤️ (@SassyCanadianCk) September 2, 2020

As many of us look to reduce plastic waste - P.E.I has already outlawed plastic shopping bags while B.C., Nova Scotia, Newfoundland, and Quebec look to do something similar - milk bags might actually be the better option. 

Many argue that milk bags use 75 per cent less plastic than a jug and can be washed and reused for other purposes. MILKBAGSunlimited in Toronto, for example, uses discarded milk bags to makes mats and mattresses as well as purses, totes, handbags, and slippers.

Mission accomplished!!! I dropped off 5 milk bag mattresses for MILKBAGSunlimited. Way to go Jackman Eco Team! You have successfully reduced waste in the best possible way. @JackmanPS1 @EcoSchoolsTDSB @EcoSchoolsCAN pic.twitter.com/kAZ17sypoU

— Paul Cressman (@paulcressman2) June 28, 2019

Of course, others question how eco-friendly the milk bag really is as they cannot be recycled in some municipalities.

It’s true too, in Ontario and Quebec their milk comes in bags. Visited Canada many times and bought a bag once when I was staying a week in Ottawa. Canada is a great place to visit but it’s definitely a different country haha... pic.twitter.com/RlhJuclcAD

— Gavin (@gpstrickland315) September 8, 2020

Next time you have to snip the corner off of a bag of milk you'll know why.