Sunday, June 16, 2013

Overthinking Cups 2.0: Now with 100% More Bowl Functionality


I posted last week about the cups I used while backpacking and camping. Well, it turns out I've been overlooking some really lightweight options, and the internet wasted no time in telling me so. As a recap, my favorite cup in my last post was the GSI Stacking Infinity Cup, which has max capacity of 14 ounces (414 ml) and weighted in at 1.76 ounces (50 grams) on my scale. My last article concluded that the Stacking Infinity was my favorite choice, beating out the Insulated Infinity, the Cascadian, and the Fairshare. I've since learned a little about plastics, found some other containers to test, hoping to find one container that will work as cups, bowls, and a water scoop for my wife and I. It turned out there are definitely better UL options than my GSI cups which still let me keep my luxurious practice of carrying both a cup and a bowl.

Polypropylene
I did a bit of googling, and it turns out that almost all backpacking dishware made from plastic is polypropylene (recycling symbol 5 PP). I confirmed that all the cups in my previous post had the recycling symbol 5.
Micrograph of Polypropylene - Wikipedia
Pretty much everything I found said that polypropylene has a melting point of at least 250 degree fahrenheit, with some able to handle even higher temps depending on the specifics of the plastic's composition. The take away is that any container with recycling symbol 5 PP should be able to handle the boiling water for your ramen or instant coffee without issue. I saw a few people with concerns about toxicity, or chemicals leeching into their food/water, but I didn't see anything to really substantiate their claims. I don't spend the majority of my time eating and drinking out of plastic, and there's plenty of other ways I introduce toxins into my body, so I'm not going to worry about it.

Disposable Food Containers Testing
After my previous post got a few views, people were noting here and there that they used small tupperware containers or plastic cups from single-serve food containers as cups and bowls. Someone on backpackinglight mentioned the Kraft Mac'n'Cheese single serving cups. I stopped by the local drugstore and picked up a Kraft container as well as a Kellogg's single serve cereal container and a General Mills single serve cereal container. The cereal containers looked like the might hold more volume. They all were marked with the 5-PP recycling symbol, and I could tell right away they were going to be impressively lightweight.

I wanted to test whether the lightweight containers (which were manufactured for one-time use in theory) would be suitable for use as a cup or bowl in the backcountry. I wondered whether the thin plastic walls would deform from boiling water, if the containers would be too hot to pickup without a cozy, or if their capacity would be insufficient for bowl use. For comparison sake, I also brought out my GSI Ultralight Bowl, an REI bowl, and the GSI Stacking Infinity cup that I decided was my favorite last week. The table below summarizes some basic info about each container.


TypeWeight (oz/g)Max Vol (oz/ml)Usable Vol (oz/ml)Size (dia./ht., in.)
Kelloggs0.39 / 1117 / 50213 / 384d:4 h:3.5
General Mills0.42 / 1216 / 47313 / 384d:4 h:3.5
Kraft0.42 / 1214 / 41411 / 325d:4.2 h:3
REI bowl1.48 / 4220 / 59112 / 355d:6.5 h:2
GSI bowl1.55 / 4420 / 59116 / 473d:5.2 h:2.25
GSI Stacking Infinity1.76 / 5014 / 41410 / 296d:5 h:3.25
Created with the HTML Table Generator

First thing's first: the single serve containers are impressively light. For the capacity measurements, the "max capacity" is filled to the brim. The "usable capacity" is more subjective, and was filled to the point where I was comfortable picking up and using the container to drink from without spilling - in general about 1/2 inch from the brim.

Next I dumped boiling water into each container to see how they worked. The extra thickness of the GSI and REI containers meant the plastic didn't deform as much when picking them up, but surprisingly (or maybe not, if you're smarter than me), the outside of the thicker GSI and REI containers felt just as hot as the outside of the disposable containers. In all cases, the containers were too hot to comfortably hold in a typical fashion. So initially it seemed like the handle on the Stacking Infinity would make it the winner, but the disposable cups had an ace up their sleeve...

The disposable containers all had a bit of a lip around the top edge, where the peel-back lid had been glued. The Kraft container and the General Mills container both had a nice sized lip that made it very easy to pickup the hot container and drink from it just using my thumb and middle finger, without having to touch the hot sides further down the cup. Basically, these two containers had a built-in UL handle. The Kellogg's container also had a lip, but it was too narrow to feel secure holding a cup of boiling water. Both the GSI bowl and the REI bowl had no lip, so were really too hot to handle with boiling water. In fairness, the GSI container comes with a foam sleeve to fix this, but it would add a small amount of weight.

Bowling Me Over
In my last post I settled on the GSI Infinity Stacking cup as my favorite cup, at 14 oz capacity and weighing 1.76 ounces (50 grams). Not anymore. The disposable cups are the same material, lighter, just as easy to hold, and even less expensive. The only advantages of the GSI Infinity Stacking cup are durability and graduations, neither of which are particulary convincing. I can add graduations to the outside of the disposable cups with a permanent marker that should last at least one trip. Even more telling is that I could bring four of the lighter disposable cups for the same weight as one of the GSI Inifinity Stacking cups. That means my wife and I could eat granola with milk and have hot tea in the morning at 1/4 the carried weight as that would have taken before.

The GSI and REI bowls both make terrible cups, are heavy, and don't work any better than the disposables as bowls, except that they offer a little more capacity. So in practice, when my wife and I are sharing a dehydrated dinner, I might not quite fit a full serving into the disposable bowl, but is that really an issue? No - just serve twice.

Conclusion
In the span of a week, I went from a heavy GSI cup and GSI bowl, to a lighter GSI cup but still the heavy bowl, to disposable plastic cups. Using a real world example, my wife and I went on an overnight recently where we carried two GSI bowls and two GSI Insulated Infinity mugs, for a total of 9.5 ounces (269 grams).  Doing it over again with the General Mills disposables, still carrying two cups and two bowls, would be 1.68 ounces (48 grams), with no real loss of functionality. I'd lose some capacity, but I think 13 ounces should be fine for both drinks and foods. The second helping should keep warm in the pot or cozy. I think my GSI-ware is officially relegated to the car camping kit.

Is that significant? Probably not. Was this fun to write? Definitely.

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