On the GR20, water and food are not managed the way they are on a lowland path. There is no mini-market in the next village and no tap at every junction: everything hinges on getting from one refuge to the next, and a single logistical slip can turn a fine day into an ordeal. After several crossings, here is how I handle water and food on the GR20 so as never to run dry, in the literal sense and the figurative one.
The golden rule for water
One single rule, but it is absolute: always fill your bottles when you reach a refuge. You will find a few springs along the way, but it is better not to count on them too heavily, because depending on the season they can be dried up. If you do draw from a spring, purification tablets remain a useful safeguard. The water is for drinking, obviously, but also for brushing your teeth and washing your hands in the evening. For the container, I suggest a one-litre bottle backed up by a two-litre bladder, enough to see you between two supply points even in real heat. And never leave a refuge in the morning without topping up, even if the stage looks short: on this terrain, one small setback is all it takes to turn a mild thirst into a genuine mess.
How much water and food per day
Day to day, allow two to three litres of water depending on the heat and the length of the stage, and set off each morning with full bottles: some days, like stage six at nearly 27 kilometres, leave you few chances to top up before you arrive. Drink regularly, in small mouthfuls, rather than waiting until you are thirsty, especially at altitude where you dehydrate without noticing. On food, always keep one savoury and one sweet snack within reach for the flat spots between refuges, and restock your bars and dried fruit at every stage rather than waiting until you have run out. A handful of almonds tucked into the hipbelt pocket has rescued more than one difficult end of stage. On the GR20, energy is managed exactly like water: in regular top-ups, never in a panic.
Eating: refuge or self-sufficiency
You have two options. The first is eating at refuges and bergeries, where you will find hot dishes typical of Corsica. Prices are high, because everything comes up by helicopter or on a donkey’s back, but the comfort and the discovery are often worth the cost. Reckon on €35 to €55 a day, with breakfast between €9 and €15 and an evening menu around €25. And do not skip the bergeries between the refuges: that is where you taste the real Corsican produce, from the saucisson at the bergerie de l’Onda to the famous veal with olives at Ballone.
The second option, full self-sufficiency, runs on freeze-dried food. You can heat water at the refuge, and it keeps the budget down, but your pack will be noticeably heavier. Plenty of walkers go for something in between: a few hot dinners for morale, and biscuits, sandwiches or tins for lunches and sudden hunger. If you are vegetarian or vegan, plan on as many freeze-dried meals as you can carry, because what is on offer at refuges is often limited to pasta, cheese and biscuits.
Booking your meals: a question of timing
On the GR20, eating well depends as much on planning ahead as on the menu. Breakfast at refuges is served from about 6.30am, so if you want to leave before daybreak to get ahead of the heat or a forecast storm, book it the evening before with the warden. Same logic for dinner: book it the moment you arrive, and above all get in before 3pm if you want to be sure of a hot meal. After that, you are left with the refuge shop, assuming it has not shut, to put a dinner together from whatever is there. Getting these times right saves you the nasty surprise of an empty stomach at the end of a long stage.
Bring cash, there is no cash machine
One point plenty of people discover too late: there is not a single cash machine on the GR20, and most refuges do not take cards. Everything is paid in cash, from dinner to a last-minute fix. So withdraw enough before you head up onto the trail, in Bastia, Calvi or Calenzana depending on where you start, and keep a small margin for the unexpected. Nothing is more frustrating than giving up a hot meal or a dry night for want of enough cash on you.
Next, have a look at where to sleep on the GR20, the budget and the kit to take.