Why wooden sticks for ice cream bars?

In terms of bulk price wood is about 3x cheaper than plastic. (I buy both plastic and wood materials for commercial and residential uses in my profession.) Also, wood is biodegradable which makes it safer for the environment if children toss away the stick after they eat the ice cream.

Besides the other things mentioned, wood is an insulator and is a poor thermal sink.

To explain -- have you ever tried to hold onto something plastic that's been in your freezer? It can be quite uncomfortable. (as can walking barefoot on one of those new plastic decks when it's been out in the sun).

Wood, however, so long as it wasn't soaked, can be held onto without risking a damp hand freezing to it ... both because it doesn't hold a lot of heat, but because it's an insulator, you only have to warm up the surface to make it bearable.

Texture also helps, in that it can make less contact with your skin, thus reducing the conductive transfer. (the same's true for plastic, but they have to specially mold plastic to add texture, which makes it more difficult to release from the molds)

One element is tradition. The popsicle was supposedly invented by Frank Epperson when he left a drink mixture on the porch overnight in with a wooden stirrer in it. (Some historians have questioned this narrative, however, given that Epperson claimed this occurred in 1905 in San Francisco, but weather records show that it never got cold enough in the 1905 winter there for Epperson's story to hold up.) The choice of wood, according to this traditional story, was somewhat accidental, though given that plastics were not yet available in 1905, Epperson's main choices for stirring would probably have been metal or wood. (And obviously metal would be uncomfortable to hold in a frozen treat, regardless of whether this origin story is true or not.)

In any case, Epperson later patented his invention (including the wooden stick) in Oakland in 1923 and started selling them. Again, this would have been too early for plastic to be a reasonable alternative, so part of the reason for wooden popsicle sticks may just be that they are traditional and familiar to customers.

A business seeking to make a change away from such a tradition would need motivation, either an economic reason (a cheaper but still acceptable product) or an actual product improvement. Given that wooden popsicle sticks are intended to be disposable and already function well, economics would be a primary reason to switch, if there were a cheaper material. But Memj's answer is correct here. It's simple economics: wood is cheaper in this case, which is the reason it is used for various small uniform disposable items from toothpicks to chopsticks, utilizing technology that has been in wide use since the early 1900s. (For more information on the reason for manufacturing and process on producing small wooden items cheaply, I'd recommend Henry Petroski's book The Toothpick: Technology and Culture.)

It's also important to note that some businesses actually have experimented with disposable plastic sticks. The most common type were so-called Elsie Stix or Icetix, which were distributed by Borden Dairy in the U.S. They were intended to be collectible and manufactured to be used as toys after serving their purpose in the ice cream bar. (See photos and further description here and here, for example.)

I would note that these sticks easily solved potential problems brought up in some of the other answers: A series of holes allowed the popsicle to be frozen through the plastic and thus added to adhesion. And the holes also decreased thermal mass and heat transfer, which would negate any potential discomfort from holding a piece of cold plastic, which seems to be a strange concern to me anyhow.**

In any case, these plastic sticks were undoubtedly more expensive to manufacture, but they were marketed as a novelty item. And their interlocking nature and use as a toy required people to buy more popsicles to build with them, thereby providing an economic incentive to justify the added expense.

Without such an economic incentive for "standard" disposable popsicle sticks, and with wooden sticks being traditional, there's little reason for businesses to make a switch to plastic.

** More details about thermal properties: While some plastics are somewhat better at transferring heat than wood, there are many types of plastic which would not be noticeably uncomfortable compared to wood in a small stick, even if they were solid. Note that the thermal conductivity of many standard plastics is around 0.2-0.3 W/m-K, only roughly double that of wood, which is around 0.13 W/m-K. Compare that to most metals, which could actually freeze one's hand to them, which have conductivities which are hundreds of times that big. Specific heat is roughly the same for plastic and wood, and the density of most plastics is only a little higher than birch, which is a standard wood for popsicle sticks. Bottom line is that plastic popsicle sticks would absorb heat somewhat more quickly and stay colder a little longer, but not enough to produce significant discomfort for a small, thin piece of plastic.

But, theory aside, one can easily buy reusable plastic sticks for homemade popsicles -- just search Amazon for "plastic popsicle sticks". (Here's a review comparing 26 different varieties of plastic molds, almost all with plastic sticks/handles.) And I don't think I've ever seen a review complaining about discomfort in holding them. I've also seen multitudes of baby teething toys, for example, which are meant to be frozen and are made out of plastic: the idea of a "damp hand freezing" to a small thin piece of plastic seems quite unlikely.

I think the ice cream sticks better to wood than plastic

It's all about the money. Without contacting suppliers you can find wooden popsicle sticks that come in packs of 500-1000 and the prices range from $0.0055 to $0.013 per stick. Some examples:

• http://www.joann.com/loew-cornell-craft-sticks/1157809.html
• http://www.ssww.com/item/budget-craft-sticks-CS425/

The closest comparable item that easily searchable is "plastic lollipop sticks". The cheapest I could find was a 50 pack at $0.0382 per stick, but most were in the $0.085 range:

• http://www.kitchenkrafts.com/product/Plastic-Sucker-Sticks-Primary-Colors/
• http://www.rakuten.com/prod/100pcs-plastic-lollipop-sucker-sticks-for-chocolate-cake-candy-mould/275891293.html

As for the thermal 'feel' of the popsicle stick, you can find lots of reusable sticks and molds for home use and they are exclusively plastic. I own a set of the Zoku brand and have never found holding the plastic to be uncomfortable after being stored in the freezer.

I am not for the bounty, because my answer is by no means complete; but I would like to share my experiences / what I have come to hear with regards to this.

I once had the very same question in mind, while I was at my neighbors during a summer day in the western part of Germany. She had some home-made ice-cream bars for the children. The sticks were made out of wood.

Her answer was simply „Well, it’s just what they did in the old past, with wood; I carved these sticks out of wood from the logs my husband chopped. But how could I fabricate plastic sticks at home, even if I wanted to?“

Another answer I received was from a man, who worked for a candy company in Germany. He was not really sure why, but claimed that one of the reasons is that some ice-cream bars consist of corn syrups and other syrups that are some what acidic; with plastics, no matter how safe they are claimed to be, breaks down over time by the acidity from the syrup and while it is not an immediate health concern, but might be over the course of time.

Another reason he said, was that one cannot be sure what might occur during the course of delivery by other vendors. If it so happened that the weather is hot and the freezer in the delivery truck malfunctions, it would be highly likely that the melted ice-cream would not stick as „good“ when it is once frozen again to a stick that is made out of plastic than a wooden one.

Again, just sharing what I have heard.

Personally, I like sticks that are made of wood. It feels better; and as far as tradition is concerned, it reminds of the old times how people were used to enjoy / make things and the way they were used to cook that was more natural.

I think the main reason is for technological reasons:

• Price (other users says wood is cheaper than plastic)
• Grip (no one mentioned, but wood should hold ice more strictly than ice: a flat plastic stick will just make the ice slide away)

Regarding thermal sink mentioned by @Joe , I'm not convinced, I remember I had (when I was a Child) plastic shapes to make homemade Ice Lollies, they had even plastic sticks but they were not cold once removed from freezer (unless those had a special plastic and not a common one).

One major factor besides economics which no one has taken up is consumer perception. Even if you use a biodegradable plastic which may have a lower carbon footprint people will perceive a wood stick as more natural and therefore more environmentally friendly.

Which is not to say that plastics have not deserved their bad wrap.

Another issue is the recent scandals caused both by plastic toys leaking toxins and Bisphenol A in water bottles might have made mother a bit more attuned to what their children are putting in their mouths.

Even if the fear may not always be completely rational since the ice cream is wrapped in plastic... People will be people.

Because plastic leaves behind toxics, whereas wood doesn't.