Hot water for coffee
One of the BEST, BEST BESTEST things we took with us was a spiral immersion heater to boil water in a cup. You will also need a two pronged plug for Spain. Although not all albergues have kitchens, most have electricity (we even used a shaving plug in the men's toilet!). We were the envy of many pilgrims who needed their morning caffiene fix and often had a small queue of cups waiting to pop in the heater. Well worth the extra weight. We also used it to make cup-of-soup and boil tinned veges.