How are milk cartons made?
In 1940, polyethylene was introduced as the waterproofing material. Refillable glass bottles reigned for a long time after milk cartons were introduced, but by 1968, over 70% of milk packaged in the United States went into paper cartons. The manufacture of milk cartons is actually a two-step process, at two different locations.
Why did they change the shape of the milk jug?
The new jug is more square - prompting a slight tilt in the usual instructions. So why this change in dairy design? "Because of the shape, traditional milk jugs can't be stacked, so they're shipped in milk crates. But they waste space on delivery trucks and millions of gallons of water are used to keep them clean."
Why are soft drink bottles round but milk cartons square?
Why are soft drink bottles round, but milk cartons square? The milk carton is more utilitarian, being more space efficient, and having a handle for ergonomics. Why then have soft drinks not followed this design?
Why don't milk cartons have a cap?
(The milk carton does not need a cap, you might note.) Van Wormer produced his original milk cartons in paperboard. And so they are today, but generally with a slick polyethylene coating, so they don't become vaguely wet to the touch once the milk soaks through. As with the refrigerator, it took the milk carton two or three decades to catch on.
Why do milk jugs have circles on the side?
If the jug hits the ground or any other surface, the circle expands to keep the milk on the inside of the plastic. Along with keeping the jug from blowing up if you drop it, it also keeps it from popping in the refrigerator. If you leave milk in your refrigerator too long, it is going to build up gas.
Why do milk jugs have dimples?
Milk contains microbes that will expel gases over time. As those gases accumulate, pressure within the jug builds up, and it's that flexible dimple that stops the jug from exploding.
Why are Costco milk jugs shaped like that?
The square milk jug is a variant of the plastic gallon (3.785 litres) container of milk commonly sold in the United States. The design was introduced in the summer of 2008 and is marketed as environmentally friendly because of the shape's advantages for shipping and storage (better cube efficiency).
What shape is a milk carton?
The shape of the conventional milk carton is called gable-topped. The top-sealer forms the gable, and heats and presses the top seam together.
Why do milk cartons swell up?
Bacteria feed on the contents of the pouch and produce gas. Since this gas cannot escape from the sealed packet, it accumulates inside and causes the pouch to bloat.
What is the hole in the milk?
The feature of this circular indentation? To let the jug expand. That's right. Expansion is necessary for a couple different reasons; one of which you might find incredibly useful.
Why did Walmart change their milk jugs?
The jugs are cheaper to ship and better for the environment. The milk is fresher when it arrives in stores, and it costs less. Sam's Club says it is saving 10 to 20 cents a gallon. “I hate it,” cafe owner Lisa DeHoff told The New York Times.
Why does Kirkland milk last so long?
The process that gives the milk a longer shelf life is called ultrahigh temperature (UHT) processing or treatment, in which milk is heated to 280 degrees Fahrenheit (138 degrees Celsius) for two to four seconds, killing any bacteria in it.
Who designed the milk carton?
Meanwhile, the inventor of the milk carton (warning: this title is disputed by about a million people) took out his patent in 1915. His name was John Van Wormer and his milk carton was basically the same as the one we use today.
When did milk start coming in plastic jugs?
1960sPLASTIC MILK JUG The design of plastic milk bottles evolved quickly in the mid-1960s, when the handled jug as we now know it was invented. The design not only saved dairies money, it encouraged customers to buy a gallon of milk at a time, a large amount compared to the smaller quantities sold outside the U.S.
What can I do with a milk jug?
21 Creative Ways to Upcycle Your Milk Jugs and CartonsWATERING JUG. keep your plants happy and well watered with this easy project.KITCHEN COMPOST HOLDER. use empty jugs to upcycle food scraps into compost.GARDENING MADE EASY. sow your seeds. ... BIRD FEEDERS. functional. ... SUPPLIES CADDY. ... FUN GAMES. ... PIGGY BANK. ... ARTS AND CRAFTS.More items...•
What is plastic milk?
We call this plastic milk but it technically isn't plastic at all! Plastics are composed of molecules that repeat themselves in a chain, called a polymer. Instead, you made a substance called Casein. Casein is a molecule of protein in milk that is extracted when the milk meets the acid in the vinegar.
Why do milk jugs have circles built into their sides?
But when you picture the quintessential gallon of milk, it has circular dimples on its sides.
Why do milk jugs have indentations?
The indentations allow the jug to expand slightly to accommodate that extra air, which is why you sometimes see the indentations poking outward. That’s also a good indication to double-check the expiration date. The older the milk is, the more likely the jug is to bulge outward.
Why are milk jugs circular?
The circles built into milk jugs provide several benefits, but the specific reason those circular dimples exist actually isn’t specific to milk at all. The circular indentations allow the milk jug to flex slightly, rather than keeping a solid, rigid shape. This is super important if you ever happen to accidentally drop a gallon of milk. Rather than cracking or shattering, the semi-flexible plastic used to make the jug, along with the indented design, allows the jug to take a harder hit.
Does milk expand when frozen?
Like water, milk expands as it freezes. The circular indentations allow the jug to expand as the milk freezes, then pop back into place whenever you eventually thaw the milk out. So, there you have it.
Can you freeze milk before its expiration date?
That’s also a good indication to double-check the expiration date. The older the milk is, the more likely the jug is to bulge outward. If you tend to buy more milk than you can use before its expiration date, you can totally freeze it — also thanks to those indentations. Like water, milk expands as it freezes.
What is the milk carton?
The Surprising History of the Milk Carton. A humble paper product tells a story of farming, waste, and home technology in 19th- and 20th-century America.
When farmers turned to mechanized milking at the beginning of the 20th century, did some of the small farms?
When farmers turned to mechanized milking at the beginning of the 20th century, some of the small farms got bigger, and production increased.
How long did it take for milk to catch on?
As with the refrigerator, it took the milk carton two or three decades to catch on. People had become attached to their glass milk bottles.
What is the purpose of a concave circle on the side of a milk jug?
According to Distractify, the concave circle on the side of a milk jug provides structural integrity. A full gallon of milk with flat, rigid sides may be fine sitting in your fridge, but if you were to drop it on the floor, it would likely rupture. The dimple can prevent that from happening.
Why is milk jug flexible?
Milk contains non-harmful microbes that expel gases over time. As these gases accumulate, pressure in the jug builds, and the flexible dimple stops the jug from exploding. An even more extreme example of this can be observed when you put a milk jug in the freezer. Liquids expand when frozen—that's why if you try freezing a bottle or can of soda, you'll end up with a shattered container and a mess in your freezer. The inverted circle on a milk jug accommodates this expansion, so you can stick your milk directly in the freezer without transferring it to a different container.
Why are Coke bottles round?
Glass bottles were invented round, because they were made by manually blowing liquid glass, and it is very hard to blow a non-round bottle.
Why is coke round?
Basically, coke with its gaseous nature, exerts more pressure per volume than Milk and to balance it out, round shape fits it well for coke, because round bottles take the pressure evenly, while square bottles get the corners chipped due to uneven pressure.
Is Coca Cola made of glass?
By now, the original constraint for creating a round bottle is long gone, as it is not even made of glass any more. But by the time Coca cola switched to plastic bottles, the existing bottle shape was already an iconic part of the brand.
Is milk carton more utilitarian?
The milk carton is more utilitarian, being more space efficient, and having a handle for ergonomics. Why then have soft drinks not followed this design?
Can you pour milk into a coffee?
People pour the milk into a coffee, cereal, etc. The handle allows the user to pour it more precisely. Soft drinks. People usually drink directly from the container - Specially the drinks under 500 ml. They need to be resistant and also have a reliable lid because people will put it in their bags, etc.
Can you drink milk directly from a container?
People don't really drink directly from the container. People pour the milk into a coffee, cereal, etc.
Can you fit more liquid in a square container than in a round container?
You are able to fit more liquid in a square container than in a round one.
Where is the gallon jug shifting?
The shape of the iconic gallon jug itself is shifting in stores like Sam's Club.
Do flat top milk jugs need to be washed?
The new flat-top jugs can simply be stacked and shrink-wrapped. No need for washing. The new containers also store 50 percent more milk per cubic foot than the old jugs. That means more milk on each truck - reducing delivery trips and fuel costs.
Background
The Manufacturing Process
- Making the paperboard
1. 1 The heavy paper used for milk cartons is categorized as a type of paperboard. It is typically made on a Fourdrinier machine, one of the oldest and most common types of papermaking equipment. The process begins with wood chips. The chips are heated and bathed in chemicals … - Applying waterproof coating
1. 2 The dried paperboard next moves through the rollers of an extruder. As the paperboard is pulled through the rollers, the machine extrudes a small amount of molten polyethylene. The polyethylene clings to both sides of the paperboard in a thin film. Several grades of polyethylen…
Quality Control
- Manufacturers make quality checks at every step along the manufacturing process. The pulp must be inspected to make sure it is the proper color and density, and has the desired fiber characteristics. As the pulp is a blend of long and short fibers, from soft and hard-wood trees, batches may differ according to the kind and proportion of trees used. The paperboard must pa…
Byproducts/Waste
- The manufacturing process for milk cartons is extremely efficient, and there is very little waste. However, most used cartons are thrown in the trash and end up in landfills. It is possible to recycle them, though, if the appropriate recycling facilities exist. A milk carton recycler collects empty cartons from large users such as schools and hospitals. Then the recycler shreds the cart…
The Future
- Milk carton manufacturing has not changed dramatically for many years, because the process is already highly streamlined and efficient. An increasingly popular modification to the tradition gable-topped carton is the addition of a plastic pour spout, but this requires only minor changes in the manufacturing process. As milk consumption falls in the United States, future changes migh…