Mead has many different meanings. In Finland, it is a drink made of white or brown sugar and lemon. It is merely carbonated by fermentation, so that its alcohol content is neglible. The fermentation changes the taste of the lemon from sharp to soft. Mead is drank only on May Day, much like mämmi is eaten only in Easter.
This recipe can be found from all packages of brown sugar.
The sugar can be brown sugar, but you can mix white sugar with it or even make the mead of white sugar only. Taste is better with 100% brown sugar.
First, boil a part of the water and pour it on the sugar. Wash the lemons carefully from the outside. Then cut them up, with the peels, into thin slices above the mead, such that the juice isn't lost. You can squeeze some of the juice out. Leave also the peels in to give taste. (Don't cut them up elsewhere - the juice is lost. Don't use anything else than fresh lemons. I've tried lemon concentrate once, and that batch tasted bad.)
Pour the rest of the water in. When it has cooled down, insert the yeast. Do not kill it by putting it into hot mead. It may be tempting, but don't exceed 1/4 tsp, because the taste will be affected. (If you want alcohol into it, use a better yeast than baking yeast.) Let it ferment (covered) for 24-36 h.
Then remove the pieces of lemon and bottle the mead. Put some raisins into each bottle. Leave them into a cool place, like a cellar. When the raisins gather enough carbon dioxide to rise up to the surface, the mead is ready. This takes about a week. The bottles gain enough pressure to eject a rubber bottle top.
A fun fact: As you know, raisins are dried grapes. When you put them into the mead, they get their moisture back. The carbon dioxide is evenly spread to the whole volume, including the inside of the raisin. So, when you open the bottle, bubbles form inside the raisins, and they rise to the surface fast. When you bite the bloated raisin, it sizzles.
Don't drink the sludge of yeast in the bottom. If you have done so, eat 1-2 dl of blueberries or a cup of blueberry yoghurt immediately. Other yoghurts may also help. Blueberry has some medicinal properties, which can cure or ease stomach pain.