I have seen some recent posts lately about Gaggia's reputed lack of steaming capabilities for large quantities of milk; 10 ounces or so.
Complaints ranging from having to cycle the boiler several times or complaints about feeble steam production. There are even complaints from non-Gaggia owners!
Most of the complaints seem to be from new Gaggia owners that are still on the steep end of the learning curve so here are some tips on extracting the best steaming performance from your Gaggia:
1. is your steam thermostat working correctly? Some thermostats, even new ones, run way too cool. If your "ready" light switches on and off a few times before your milk gets to 160F, your thermostat is clearly defective. Get rid of it and get a new steam thermostat - a two minute job.
2. ease up on the purging. If you bleed your steam wand too much in order to get "dry" steam, there might not be enough steam left over to do the job.
3. you can try one of the following methods to see which one works best for you:
a) do your bleeding/purging while the boiler comes up to steam temperature. When the "ready" light comes on, start steaming.
Yes, the steam will start to diminish fairly rapidly, however the light should go out indicating that the powerful boiler heating elements have kicked in. You should have plenty of steam power to carry you to at least 140F before the "ready" light comes on and steam starts to diminish once again. You should be able to coast to your end point of 155F -160F. If you can't reach 140F before the light comes on, you need a new thermostat!
b) this last method is a bit trickier to do, however it should give you the best quality steam if you can time it correctly. Do your initial purging first. Here's the tricky part. Start steaming just before the red "ready" light comes on. You want to keep the boiler elements going full tilt for as long as possible. If you catch it just right you can just about spin 10 oz of milk right out of your frothing pitcher!
My usual method is to start purging almost immediately after flipping the switch. I purge at least twice, briefly at the end but early on I will sometimes let it ride for a bit, to boil off some water and give myself some more headroom (if I have the time). The key, as Glenn points out, is to steam with the element on. I start steaming early, many seconds before the temperature-ready light illuminates.
How much milk you steam depends on your expectations and your steaming vessel, imo. You could froth copious amounts of milk if you are happy with coarse foam (Glenn is certainly not) or even good dense foam, but producing decent microfoam can reduce the quantities some. You need to be able to fold the milk over itself continuously, which can become difficult with lots of milk and especially if you have a large pitcher. This task generally wants for a fully-open steam valve, further complicating steam recovery.
The pitcher should match the volume of milk being foamed. The narrower your pitcher the better, while still large enough to contain your milk during spinning. My ideal pitcher, I think, would be about 14oz. My 10oz jug is big enough for traditional cappas, but a bit small for pouring an 8oz latte -- attempting the last risks spinning milk out of the jug. I have been using a 20oz jug for those, but the dimensions of the jug makes folding the milk difficult beyond about 8-10oz. Heating the milk to temperature is never the issue; maintaining a strong "whirlpool" to constantly mix and re-incorporate the foam is. The trick is in maximizing the spinning time before you get up to temperature.
Technique, of course, is a factor here as well. The more mature your technique, the more successful you will be at achieving the desired results despite less than ideal conditions (too much milk, too little milk, incorrect pitcher size or shape).
Being able to reach down into deeper pitchers, far enough to be able to spin the milk properly and incorporate all of the milk, well ... that is another story. Some froth with the bare wand, though it has a large hole and leaves you rather short. Others froth with only the inner portion of the turbofrother (either the Gaggia or Saeco wand, which looks better). Still others adapt their technique or adjust their frothers to cut off the air intake, allowing them to froth larger amounts in deeper pitchers. I have been working with the last for a little while now, and while a bit harder to control the stretching it can be made to work -- for the newer-style frothing aids, you slip the red o-ring down one space, cutting off the air flow and allowing a product rather close to microfoam, if still often a little coarse.