Home brewing started for me when I was skint and was going on a weekends camping trip with a bunch of other skint but thirsty people. The resultant brew carefully bottled was disgusting, rank and foul. We drank much of it over the weekend.
Once I'd equipped with a pressure barrel the fun could really start; you see the problem with bottle conditioned beer is your either put too much sugar in the bottle, making it explode, or you don't seal the bottle top properly, making it go rank. With a barrel that has a pressure release valve the former does not occur and with only one aperture, the latter is unlikely.
Basic brewing kits supply the malt impregnated with hops and other additives, and the yeast. All you do is add hot water to dilute it and keep for a couple of weeks to ferment in a tub, then siphon into a barrel and leave for a month. Hey presto ! five gallons of drinkable ale or lager. You can't really escape the 'brewed at home' taste but nevertheless its yours so you can pig out to your hearts content !
The really tough bit I've never mastered is preparing your own malt. The science is that grain of all types is packed with carbohydrate which turns to sugar (dextrose I think) at the point of germination (i.e. when it starts to sprout). Grain germinates in warm humid atmospheres which used to be within the local maltings, where a central oven heated wetted foot deep grain spread over huge open floors. When it sprouted it would be toasted dry to stop the germination and the level of roasting imparted flavour - the more its roasted the darker the beer that would be produced, very much like coffee. At this point the brewer would make up a big vat of water and boil the roasted malt to make the 'mash' which would then be strained into the brewing tub. This mash would now be a mixture of boiled (therefore relatively sterile) water and sugary brown malt. Natural yeasts would settle on this mixture and the magic begins - although most commercial scale breweries long ago adopted a strain of yeast they kept going from one brew to another.
The magical yeasts set to work converting the sugar to alcohol until eventually it runs out of sugar (for a light ale) or poisons itself in alcohol. Most beer yeasts cannot tolerate an alcohol content much about 7% and this is why beers tend to top out at that limit. Stronger beers are 'fortified' with spirits.
My only attempt at doing the whole process from scratch led to a complete failure - I suspect I didn't have a dense enough mash and there wasn't enough sugar to start fermentation. However there is always another day ...
Cider making is very different to beer as the only ingredient needed is apples. Probably about four crates of apples makes five gallons of cider. The only drawback is the requirement for a cider press - apples don't give up their juice lightly (see the sidebar for a good yarn about how damned hard it is to get out the juice). You first bash the apples about a bit with a huge lump of wood (a fence post does fine) and then load them into a steel press. I've got a nice one from Burghley Homebrew (see side panel) which works on a ratchet system which means that small children can assist without needing to look like Thor or Popeye.
Once the apple juice is squeezed out (the rule is - if you wouldn't eat the apple, don't put it in your cider press. Old timers throw anything not actually wriggling in the press, but they look deranged, and I wouldn't trust them) you put it in a tub with a loose fitting lid or old net curtains over them, to keep out the vinegar fly, then seal in bottles after about two weeks. During this time the yeasts naturally settled on the apple skins will have done their magic - however do be aware that 'supermarket' apples are polished and pesticided, and fungicided and therefore are practically sterile - get some Cider Yeast from a home brew makers or you'll end up with lovely stale apple juice.
Having been equipped for cider and beer making, when I had surplus plums this year and had finished making jam out of them, I had enough to make some wine. The basic process is like beer making - boil the fruit in water to get the sugars and flavour out, then siphon off into a brewing tub (in the case of wine this is traditionally a glass demi-jon) add some yeast and leave to ferment with access to oxygen. Once this aerobic fermentation has started the real business begins. Wine yeasts are anaerobic fomenters who need an oxygen free atmosphere to thrive. You get this by putting a small water trap on the top of the demi-jon and the carbon dioxide excreted by the yeasts drives out the oxygen and it bubbles away vigorously for several months.
Once its stopped your wine will probably be at 11-14% at which point the yeast dies and you can siphon off the wine. Its perfectly drinkable at this point but not clear - so most brewers will add a little clarifier (typically a kind of extremely fine brewers clay which draws down the particulates over several days) and will repeatedly siphon off (called 'racking') into new bottles until clear. Amateurs like me however just bottle it and drink it. Plum wine was pretty good with Christmas Dinner this year.