hey, I'm a barista and wanted to add my two cents to the query about 'sour milk.' when you burn milk it will taste sour, so I think thats pretty much the same thing. if you overheat it, you burn it. steamed milk is always more enjoyable when its not crazy hot anyway, but if you want it extra hot then only steam a few seconds longer. you will be able to tell by the smell, if you've burnt it then it will smell sour and not sweet.
I watched like two hours of steaming milk tutorials on Youtube last night and took a nap.
I feel like I suck at my job, but I can get away with it because yuppie midlothian assholes don't know what's good or bad. But, I want to be good at it for myself. Also thinking about getting a home espresso machine so I can practice. Even though, I know those are not as good as the ones at like.. real shops. Plus, that's money I don't have.
I feel like that's a very music major thing to do. Being so concerned about being good at something, finding a way to practice it at home.
BRIAN TEACH ME YOUR WAYS.
So I've been training coffee skills into people in the last few weeks. We're getting new hires soon, so I spent my bike ride home making notes on what works best for teaching, and I'm putting them online since pretty much all the coffee skills info I could find online was for enthusiasts who don't have to worry about getting three or four different orders to waiting customers.
(Disclaimer: coffee standards vary across businesses - I'm not sure how much my place's match up to Starbucks norms - and my coffee skills are mostly self-taught and a product of me being a massive geek! Still, lots of this is analysis that you can use to make tasty stuff with an espresso machine.)
BASICS
Espresso machines can make three basic kinds of drink: espresso itself, espresso + hot water (= an americano) and espresso + milk (a latte, cappuccino, mocha, macchiato or flat white).
ESPRESSO
just make sure the group head and the machine's filter are clean and your espresso cup is heated, then just pull the shot. nice and straightforward! (do just be aware that because you're serving the coffee and nothing but the coffee, it'll really show up if your coffee grind is wrong or badly tamped, or if the machine isn't nice and clean and correctly adjusted.)
AMERICANO
some machines will measure out an americano for you. this seems like cheating to me! if yours doesn't, pour the shot into the water instead of just topping up with water, or it'll scald away the crema.
MILK-BASED DRINKS
there are long and furious debates in all levels of coffee nerdery about how to define all these drinks, but a J. Average Customer asking for a LATTE wants a long drink with a touch of extra rich creamy milkfoam on top and her cousin asking for a cappuccino wants a stronger coffee with a cap of milk on top. it's pretty universally agreed that you should pour milk INTO a latte and ONTO a cappuccino, so in the latte it's evenly mixed through and in the cappuccino you end up with a pretty white space with a ring of coffee-colour around it on.
this means you need more air incorporated into cappuccino milk, but also that your pouring technique needs to change. first, though...
STEAMING MILK
commercial espresso machine have two boilers, one for keeping a reservoir of water to push through the filter heads to make espresso, t'other generating steam to expel from what all their manuals insist on calling a 'steam wand'. this does two things to milk: it heats it and moves it around. held low in a milk jug, it mixes the milk it's near with milk it's further away. held near the surface, it mixes the milk with air, and therefore gives it more volume.
held too near the top of the milk, it'll pull big bubbles of air in, pretty much like running a tap into dishwater. this does not make for delicious or awesome looking coffee. held too low, it'll heat milk much quicker than it adds volume - you want milk at or under 70 degrees C or 150ish F.
what you're aiming for is getting air in gradually, so it makes tiny little bubbles and the milk ends up with a smooth texture and a bit of a sheen to it. for a latte you want that effect and enough extra texture to give the milk a bit of foam at the top, so you can do that until you get enough volume then plunge the steamer arm deeper and heat it up. you can safely leave it so long as you have an eye on the temperature; it's stable now, time for prep!
if you have more air than you want in the drink or nothing better to do, tilting the jug so you're aiming steam towards one edge of the bottom of the jug will make a whirlpool - that'll mix the bubbles of milk from the top through the whole jug, knocking out any extra air you don't need.
for a cappuccino you've likely to much want to be adding volume throughout and making careful adjustments so the steam arm's always at the right height. remember to forward plan: the milk should double in size by the time it gets up to temperature, so choose a jug appropriately if you're making multiple drinks! only reuse old milk for it if it's a good quality and already appropriately volumised, or you'll risk making a lacklustre drink.
when I was first learning coffee skills, someone told me I wanted the steam arm under half a centimeter of milk at any one time, and I kept trying to just judge the distance by eye. it's a useful rule of thumb, but nowadays I find it easier to listen and look not for benchmarks but for what the milk's doing: you want a little bit of a whirlpool, some movement. sometimes rather than raising or lowering the jug to adjust depth, you can just tilt it - especially if you've messed up and got too much air in. tilting means you're moving milk around the surface more than up and down again, it's good for rescuing sad separated bubbles.
another useful trick is to start learning to do this less by listening: a dull roar is bad. near-silence means you're heating the milk without texturising it. a quick-shifting chhkkk sshkk sound is good: that means gets milk gets to touch the air for a second then gets pulled back under by the vortex the steamer arm is making.
POURING DRINKS
pour a latte straight from the spout. pour a cappuccino from the side of the jug onto the side of the cup so it'll land within but near the edge of the espresso shot, tipping both vessels upright as you go, like you're pouring beer from a bottle into a pint glass. you should get a circle with a crema outline, and if you drag the jug towards the far edge of the cup as you finish the shot, you can make a heart!
SPEED AND TIMESAVING
coffee geeks who geek about coffee from the privacy of their own home have spent a whole load of words telling the internet how they keep milk jugs in the freezer and start every drink afresh, possibly only after they've said a prayer to the gods of caffeination and consecrated their machine.
if you want to be able to serve ten different drinks in four minutes, that shit isn't practical. judging how much milk you need for a drink is a good skill, learn it and apply it if you want to practice latte art, but left-over well textured milk isn't going to stop being good for the next drink. if it's got a topping of dry foam or it's cooled down loads, chuck it, if not, just pay attention and make judgement calls. when my place is been busy I'll make cappuccinos and lattes from the same milk by taking a few seconds foaming time away and then using the more airy top half for the first drink and the thinner second half for the second. (HERESY, cry the home-barista forums, but, if you're working in a cafe you are probably not paid to make really great drinks 100% of the time so much as to Get Shit Done. get that shit done, and geek over your drinks as when the opportunity presents itself! and learn interesting shit from ways you try to save time, that too!)
anyway, my dudes got most of that plus How To Clean The Coffee Machine (and one of them got the seriously, dude, clean it or else remix), but that shit is interesting to NO-ONE ON THE WHOLE INTERNET, including me. those sure are a lot of coffee tips! congrats to anyone who's read them all :>
