Iso COZY

Development Story / 開発ストーリー

■ Development Notes The gas used as fuel is also part of the weight. The thermal energy converted from burning fuel can also be considered "weight." When I hiked the long Pacific Crest Trail (PCT), I made my own food cozy (insulating cover) to use while walking the PCT. I would put freeze-dried food into boiling water, or reuse containers from commercially available outdoor food products, putting ramen noodles and powdered mashed potatoes inside to make simple meals. Because my cooking style focused primarily on keeping food warm, I was able to significantly reduce my fuel gas consumption. While other hikers had to buy gas canisters every time they descended to town, I only needed to buy them about once a month. I realized that a food cozy is an effective tool for saving fuel on the trail. In the PCT photo samples, we had already tested using lightweight, high-performance supercritical foam insulation, and we realized that it offered the best balance of heat retention and lightness. However, while considering the package sizes of dry food in the US and Japan, we thought that if the size was compatible with US packages, it would also be possible to store a 250-size cooker. The flap has a buckle closure, which allows it to be used as a handle holder, and it can also be securely fastened with the buckle and belt. As a result, I have eliminated the need for a stuff sack and now store and carry my entire cooking system in this food cozy.

Design Concept / 設計コンセプト

Heat-retention design

Every heat source emits infrared radiation. The human body emits it too — but we decided that, beyond that, the insulating layer is what really matters for holding heat, so we obsessed over the insulating material itself. Most food cozies on the market use the aluminium-foil air cushions used in construction, but they have a few problems. Because there is so much aluminium, the aluminium itself absorbs heat in the early stages, and when ambient temperatures are low heat sometimes leaks out very quickly the moment the food is dropped in. The large air pockets inside an air cushion also drive convection inside, which in turn promotes heat exchange with the outside air. The same way that an air mattress feels cold in winter, when ambient temperatures are low the heat inside is easily stolen away. To maximise insulation, vacuum insulation like a thermos would be ideal because it prevents conduction — but for a light, easy-to-handle insulator we decided closed-cell foam was the best fit. Because preventing convection of air is critical, we used a closed-cell sponge made under supercritical conditions. "Supercritical" here means polyethylene resin is taken to a special state under high temperature and pressure, then the pressure is reduced to form a fine cell structure. This produces a sponge with no impurities in the base material, that combines stability, light weight, and durability. Because it isn't urethane foam, there's also no risk of degradation from hydrolysis. We also looked into whether we could add infrared reflection for heat retention without adding weight, and we adopted an infrared-reflective material. Aluminium foil air cushions used in construction have a problem where folding causes wear typical of aluminium, so for the inner surface we used a flexible aluminium-vapour-deposited polyethylene film. There are many variations of this film, so we ordered multiple samples, ran durability tests, and selected the one with the best balance.

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  超軽量臨界発泡フォーム

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  赤外線反射アルミ蒸着フィルム

Function & Detail / 機能ディティール

Inside dimensions

Width approx. 21 cm Height approx. 16 cm Depth approx. 5 cm

Dry food this fits (for reference) • Mont-bell Risotta • Mont-bell white rice 100–200 g • Satake Magic series • Onishi long-shelf-life white rice and similar emergency food • Backpacker's Pantry • Mountain House • Small Twist (Manufacturers update their products, so use this only as a guide.) At about 21 cm wide, food pouches can usually go in without folding.

Body

A flat, simple pattern. Seams are kept to a minimum to reduce cold spots. Function is the priority, so the bag is not designed to stand on its own. Most food pouches sold in Japan fit with a little room to spare. Two 350 ml cans of beer also fit. Chill the beer ahead of time, drop in an ice pack alongside, and they'll stay cold for about a night. Thanks to the strong insulating performance, it works as a cooler bag too. There is also a strap loop on the side, so a chilled drink is easy to carry. Useful at outdoor events and festivals as well.

Flap

The flap can be flipped inside out and used as a handle. The flap also has insulation inside, so even in winter your hands stay warm. The belt length is adjustable so you can operate it with gloves on. Adjust the belt and you can also stash and carry a cookpot.

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  大型サイズのトレイルフードまで対応

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  ハンドウォーマーハンドル

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  最大OD缶250サイズのクッカーを保温可能

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  缶ビール等の保温も可能

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  ストラップループ

Specs & Materials / スペック・素材