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Dry Bag Size for Food and a Cooking Kit

How much volume one day of food actually occupies

Food volume is a function of calories and water content, not of appetite. A 3,000 kcal day of freeze-dried meals, oats, oil, coffee and snack bars packs to roughly 1.4 litres and 750 g per person. The same calories in fresh food, with vegetables, bread, cheese and a tin of fish, packs to 2.6 litres and 1.5 kg because you are carrying water inside the food. That single choice moves a three-day food load from 4.2 litres to 7.8 litres for one person.

Packaging adds a third variable. Commercial freeze-dried pouches arrive flat and stay flat, and you can squeeze the air out. Supermarket packaging does not: a rigid tub of spread, a jar of sauce and a vacuum pack of rice behave like small bricks in the bottom of the bag. Repackaging into flat zip pouches typically removes 12% of the volume and about 80 g of cardboard and foil before you even start, which is often the difference between a 10L and a 15L bag.

The cooking kit: stove, pot, fuel and awkward shapes

Hardware is the part of the load that refuses to adapt. A remote-canister stove with a pre-heat tube weighs 240 g and folds to 110 mm by 90 mm; a simple screw-on burner weighs 78 g and vanishes into a pot. A hard-anodised 1.1 L pot with a lid weighs 320 g, and nesting a 0.7 L second pot inside it adds only 40 mm of height but lets you boil and simmer at the same time, which on a four-person trip is worth the 190 g.

Two items set the minimum bag width: the pot and the fuel canister. A 1.1 L pot is about 130 mm across, a 230 g gas canister 100 mm, and a 500 ml liquid-fuel bottle 75 mm. Stacked side by side they need a bag mouth of at least 150 mm to go in without being forced. A roll-top bag with a wide, reinforced mouth takes that stack in one movement; a narrow-mouth bag makes you tilt and twist, which is how welded corners get creased.

Matching bag size to trip length and group size

The formula that works in the field is litres = 1.6 x people x days + 2.4 for the hardware, then round up to the next stock size. One person for two days gives 5.6 litres, so an 8L bag. Two people for three days gives 12 litres, so a 15L. Four people for three days gives 21.6 litres, so a 25L. The 2.4 litre hardware allowance assumes one pot, one stove, one canister and a wash pouch; add 0.8 litres for a second pot or a coffee press.

Round up harder than you think you need to. A roll-top bag loses 2.5 to 4 litres of usable space on a 20L when the mouth is rolled three times, and food bags are usually packed to 85% so the closure still seals around a bag that has been opened and re-closed four times a day. Treat the calculated figure as 80% of the bag volume you should buy, not 100%.

One big kitchen bag or several smaller ones

Split the kitchen into three jobs and the whole system becomes easier to live with. The food bag is opened once or twice a day. The hardware bag is opened at every meal and gets wet, greasy and sandy. A small third bag holds what you need at the next stop: coffee, sugar, snack bars and the spoon, so you are not unpacking 20 litres on a windy bank to find the sugar.

Redundancy is the other argument for splitting. A single 30L bag holding 11 kg of food and hardware is a disaster the moment a closure is compromised, and it is also an awkward shape to lash into a canoe or a kayak hatch. Three bags of 4 kg each distribute weight where you want it, pass hand to hand on a portage, and mean one failure costs you breakfast rather than the entire trip. Groups of four or more should split food across two bags for exactly this reason.

Fuel, ignition and what must never share a bag with food

Fuel and ignition live separately from food, always. A butane or propane canister can weep a small amount of gas through a valve that has been knocked in transit; propane and isobutane are heavier than air and pool in the bottom of a sealed bag. Nothing about that is dangerous in an open, vented space, but it will taint bread, chocolate and coffee within hours, and a tainted food bag is a ruined trip on a long carry.

Liquid fuel is a stronger rule, not a weaker one. A 500 ml bottle of white gas or kerosene that leaks inside a food bag makes the contents unusable and leaves a residue that is very hard to remove from TPU film. Keep fuel in its own small roll-top bag or in the original vented container, carry two ignition sources in different places, and never put a lighter in the same bag as the stove hose where residual fuel sits.

Odour, grease and why the food bag needs its own colour

Grease is the one substance that tests a waterproof bag in a way water never does. Cooking oil, cheese and cured meat leave a film on the inside of the bag that attracts dirt, holds odour and, over a season, makes the film surface tacky. Wipe the inside of the food bag with a diluted dish soap solution at the end of a trip, rinse with fresh water, and dry it open in shade before it goes into storage.

Colour coding removes an entire category of mistakes. Assign one colour to food, a second to hardware, a third to the wash kit, and never cross them. On a dark morning, a camo food bag and a pink hardware bag are identifiable by touch and by shape alone, which matters when you are packing by head torch at 05:30. Our colour range guide sets out which colourways stay visible after a season of UV exposure.

Film thickness and closure choice for a kitchen bag

Kitchen bags are abrasive environments. A pot with a rolled rim, a canister with a crimped edge and a spoon handle all move against the film every time the bag is carried, and a 0.3 mm TPU film that is fine for clothing will show scuffing within a season of that treatment. A 0.5 mm film adds about 90 g to a 20L bag and takes the contact without marking. Pair it with a 500D face fabric if the bag will be dragged over rock rather than carried.

Roll-top beats a zip closure for food for one specific reason: grit. Flour, sugar crystals and sand find zip teeth and jam them, and a jammed waterproof zip on a food bag is a genuine problem in bear country or in wet weather. A roll-top has no teeth, no slider and no tape to fail; you rinse the fold line and roll it again. The full mechanism is explained in our closure guide.

Where the kitchen bag rides: canoe, kayak, bike or backpack

In a canoe or a raft, one large bag is correct: there is space, the load is heavy anyway, and a single 30L bag wedged against a thwart is more stable than three bags that roll. In a sea kayak the opposite applies, because hatches are narrow and a 12 kg kitchen bag is the hardest thing you will ever push through a 200 mm hatch opening; split it into a 20L and a 10L and put the heavier one low and central behind the seat.

On a bike, the kitchen bag is a pannier or a handlebar roll, and the constraint is diameter rather than litres. A 25L bag rolled tight becomes a cylinder about 230 mm across, which fits a large handlebar roll but fights a standard rear pannier frame. Motorcycle and bikepacking setups are covered in the luggage setup guide and the handlebar guide; both use the same volume maths with a different shape limit.

Cold, altitude and the meals that change the maths

Winter moves the numbers in two directions at once. Calorie requirement climbs to 4,000 kcal or more, which pushes the food to 2.2 litres per person per day, and the food itself is fattier and denser, so weight rises faster than volume. Drinks count as well: a hot drink every two hours is 1.5 litres of boiled water per person per day, and boiling snow for that water roughly doubles your fuel consumption compared with melting ice.

Altitude changes fuel more than food. Water boils at about 90 °C at 3,000 m, so simmered meals take 30 to 50% longer and a 230 g canister that gives 19 boils at sea level gives about 12 at 3,000 m. Pack one extra canister per two people per week above 2,500 m, and remember that a frozen canister performs badly until it is warmed inside a jacket for ten minutes.

Cleaning a bag that has carried food

Start cleaning on the last morning of the trip, not a week later. Food residue that has dried for days bonds to the film and needs scrubbing, while the same residue wiped within twelve hours comes off with a cloth. Empty the bag over a groundsheet first, because crumbs on grass attract everything from ants to mice, and shake the welded corners where flour and oat dust collect.

• Empty completely and shake out crumbs; turn the bag over a groundsheet, not over grass.
• Wipe the inside with 500 ml of lukewarm water and two drops of biodegradable dish soap.
• Rinse with fresh water at ambient temperature; never use hot water on TPU film.
• Pay attention to the welded corners, where grease and food dust collect.
• Dry open in shade for at least six hours, then store loosely rolled with the buckle undone.

Odour that survives washing is almost always trapped in the fold line rather than in the body of the bag. Run a soft cloth along the inside of the roll, then leave the bag open in moving air for a day. If a sour smell persists, the cause is usually residual moisture in a seam channel, and a second full drying cycle with the mouth propped open solves it. Step-by-step detail is in the cleaning guide, and mildew on stored bags is handled in the mildew guide.

Weight and bulk: what a full kitchen bag does to your load

A four-person, three-day kitchen weighs 10.5 to 12 kg before water. That is more than most people carry in clothing for the same trip, and it is the single heaviest item group in the boat or the vehicle. Split it: 6 kg in the main food bag, 3 kg of hardware in its own bag, and the remaining weight in the day bag that goes forward for lunch. Nothing about the waterproofing changes with weight, but everything about handling does.

Balance the load against the trip, not the bag. In a tandem canoe, the kitchen bag should sit slightly aft of centre so the bow rides light in a headwind. On a bike, the heaviest bag goes low and forward. In a backpack, the pot and canister belong against the back panel and the soft food bag above them, because a hard cylinder against a spine is the fastest route to a bruise on a 12 km approach.

Sizing checklist for a camp kitchen

• Calculate litres as 1.6 x people x days + 2.4 for hardware, then round up one stock size.
• Measure the pot and the canister: the wider of the two plus 20 mm is your minimum bag mouth.
• Keep fuel and ignition in a separate bag from food, always.
• Choose 0.5 mm film and a 500D face if the bag will be dragged over rock.
• Assign one colour per job and never cross the system.
• Split any load above 8 kg into two bags for handling and redundancy.
• Add one extra canister per two people per week above 2,500 m.
• Compare the result with our full product line before you commit.

Retail and rental programmes turn the same checklist into a buying brief: volume, mouth width, film thickness, closure type and the test standard behind the waterproof claim are the five lines that decide whether a kitchen bag survives a season. Sampling takes 6 to 10 working days and bulk runs 35 to 50 days from FOB Xiamen.

Food hygiene is a separate discipline from dry storage. A sealed bag keeps food dry, not safe: cooked leftovers, raw meat and dairy still follow time and temperature rules, and the CDC food safety guidance is the reference we point people to for chilling and reheating. The WHO publishes the same principles for travellers, and material in contact with food should be checked against ISO standards for food-contact surfaces; our food-safe materials guide covers what to ask for.

Two further guides close the loop. The capacity guide maps every stock size from 2L to 90L against real loads, and the measuring guide shows how to check a volume claim yourself with a measuring jug. If you are building a kitchen load for a weekend rather than an expedition, the weekend sizing guide is the shorter read, and our roll-top range carries the wide-mouth geometry that pots and canisters need.