Improvising funnels and scoops

A funnel narrows the cross-section: the liquid hits a wide opening, gathers on the sloping wall and then runs in a concentrated stream through the narrow neck. That way it lands in a small opening in a controlled way instead of running down the side. A scoop works the other way round: it takes liquid out of a large open container so you can pour it on.

Before filling, every bottle is full of air. For liquid to run in, the same amount of air has to come out. If the funnel sits tightly in the opening, the air has to force its way up through the funnel in bubbles – that is the glugging. The funnel then drains slowly and easily slops over.

The solution is simple: lift the funnel slightly while pouring, or put a thin stick between the funnel and the bottle neck. Then the air can escape at the side and the liquid runs smoothly.

Take a clean drinks bottle and make sure you know what was in it before. For water and food, only food-grade containers are suitable – that is, ones already meant for drinks or food. Cut the bottle straight across at about the upper third. The top part with the neck is your funnel; the bottom part is a scoop or measuring cup.

Fresh cut edges on plastic are surprisingly sharp. Cut away from your body, ideally with scissors, and then tape the edges or smooth them carefully. This applies even more to metal tins.

For dry things such as rice, sugar or flour, a cone of thick paper or multi-layer foil is enough. Paper does not last long with liquids because it soon goes soggy. Do not pour hot liquids through thin plastic funnels or into thin plastic bottles – they deform.

The most important part of this technique is not the cutting but the separating. Funnels and containers for fuel, oil or chemicals are clearly and permanently labelled and never used for water or food. Store them separately too, for example the fuel funnel in its own bag with the fuel bottles.

Containers that previously held chemicals, oil, fuel or pesticides are off-limits for drinking water and food – even after thorough rinsing. Residues can remain in crevices and in the material. Authorities such as the CDC and Ready.gov advise storing drinking water only in clean, food-grade containers.

Fuel never goes into drinks bottles. A water bottle filled with methylated spirits looks just like a water bottle filled with water – mix-ups can lead to poisoning, especially in children. For fuel, use only containers made and labelled for it.

A funnel only transfers water – it does not make it any cleaner. Rainwater, water from a stream or pond and utility water stay exactly as they were. Before you drink water like that, it must be disinfected, for example by boiling. Follow the advice of the authorities when doing so.

So that clean water does not get contaminated while decanting, rinse the funnel beforehand and do not touch the inside. Ideally, use different, labelled funnels for drinking water and for utility water – such as water for flushing the toilet or for the garden.

The scoop made from the bottle base should stay clean too. Do not dip it into a drinking water supply with dirty hands; hold it by the rim, or better pour straight from the jerrycan.

Decant fuel only outdoors, away from flames and only once the stove has cooled down completely. Fuel vapours can ignite even when there is no flame right next to them. Let spilled fuel evaporate before you light the stove.

Keep fuel and chemicals out of children's reach, in their labelled original containers or suitable fuel bottles. If someone has swallowed something poisonous, call the local emergency number (112 in the EU) or your regional poison control line.

Watch your fingers when cutting. Cut away from your body on a firm surface and tape sharp edges straight away. A well-made bottle funnel lasts a long time and saves a lot of spilled water.