The attributes and usage of the Sunbeam vacpots have been well covered by some of the good reviews posted here, so this review will not rehash them. Rather, I will concentrate on overcoming some of the misconceptions and complaints about these devices you sometimes see.
Not having used a C-50 or C-20, I’ll confine myself to the most common version seen, the C30 variants. The C-30 is found with either a cloth filter rod generally in the C30a models, or a SS mesh filter usually on the C-30b or C30c. I have used the metal mesh filter which is extraordinarily fine meshed and very effective and durable. The c-30s suffer from hardening gaskets. Treating yours with a thin coat of silicone grease will both protect it and make it much easier to use.
People who try these sometimes complain that there is a metallic taste to the coffee. I am relatively sensitive to such things, to the point that I use no aluminum cookware – even the hard-anodized stuff, since I can “taste the aluminum” quite readily. Chromium, the coating on the Sunbeams, is quite inert, and I find I can detect no significant taste flaw in the coffee from this pot. (The inside coating is chrome – not nickel, not stainless steel – chrome) I wouldn’t be surprised if there are some supertasters out there who can out-do me in this regard, but most folks are unlikely to be one of them. When I compared glass Silex coffee to Sunbeam coffee – both brewed the same amount of time, there may have been a just noticeable difference, but just that.
The other main gripe about the Sunbeams is that they are “designed” to brew too long and over extract the coffee. Others advise that you must watch the thing and unplug it at the right point in the bubbling process because it’s impossible to get it to work automatically as designed. A related complaint is that the coffee is “burned” because it always descends into a dry, hot lower chamber when it first goes south.
Yes my friends, if you try to brew coffee in a 60 year-old automated device, you may find that the poor thing needs some re-calibration to work correctly! Who would have thunk it? Fortunately, the Sunbeams are indeed adjustable.
The standard advice for vacpots in general is to use “fine” ground coffee which is finer than drip, but coarser than espresso grind. Grocery store grinders had a set point for this grind specifically for vac pots for many years. For such a grind, a brew cycle of one to three minutes is also standard advice. The coffee brewed in these machines in their heyday came from commercial grinders, which tend to have a more uniform particle size than home grinders today have – even high end espresso style grinders. Home grinders are more “dusty”, so those who grind at home will likely not want to push this brew cycle out too much, to minimize over-extraction of the fines.
An untouched-for-years Sunbeam or an otherwise maladjusted one will often run a cycle well in excess of this brew cycle window. The primary problem is that the coffee bubbles for too long, which makes the drawdown phase too extended.
If the drawdown is smooth but too slow, your coffee is too fine, and your filter is clogging, just like a manual vacpot.
For the Sunbeam though, a more typical pattern in which the drawdown is not smooth will look like the following. Not all Coffeemasters that have been in some closet for 50 years will behave exactly like this, but let’s say this is a representative example. Let’s also assume the pot is about half full of water:
1) The machine heats up, water goes "north" and starts to bubble
2) the machine bubbles vigorously for 75 to 90 seconds,
3) The bubbling quiets down and stops
4) Very quickly after the bubbling stops, the machines switch trips, from HI to LOW, turning off the heat.
5) After a pause, the coffee just begins to draw down, but then the machine goes into another mad bubbling fit before subsiding again.
It’s possible for this bubble/subside cycle to repeat several times – greatly extending (and wrecking) the brew. What’s happening is that the bottom vessel boils dry before the thermostat turns down the heat. When the coffee tries to go south, the too-hot bottom vessel boils and “burns” the first liquid to descend, starting the bubble process over again. Depending on how much water you put in the pot to begin with, it’s also possible for the pot not to go dry, but still bubble for more than the 75 second interval and accumulate too much heat, extending the drawdown and similarly ruining the brew.
The answer is to reset the HI thermostat so that it kicks in while there is still some water in the bottom, and a better interval for brewing has elapsed. In my experience, and with my preferred grind, this is in the range of about 40 to 55 seconds of bubbling, though others quote both shorter and longer times. The varied advice given about this timing probably has to do with the fact that people use different grind sizes and make different batch quantities, plus some people are less knowledgeable about brewing “best practices” than others.
My interval results in a brew cycle total of about 2 to 2.5 minutes including a smooth drawdown, without any burning or burping.
There is a second thermostatic control for the LOW “keep warm” setting. Check the temp of the coffee or of a test batch of water 5 minutes after brewing and make sure this setting is not any higher than 180 degrees or so. This setting only turns on some heat when the temp falls to its set point, to keep the coffee warm. Contrary to what you sometimes read, it will not affect the brew cycle time unless grossly maladjusted to the high side. I have yet to find an old Coffeemaster in which this setting was too high.
Any rust or dirt in the switch that cuts off the High bubbling phase will cause the machine to be inconsistent and hard or impossible to calibrate, but I have only encountered this once in machine that was badly rusted underneath. All other machine I’ve seen have been fine, and run consistently.
For a nice intro on how to adjust these settings, you can search the Homeroast Digest site for “sunbeam coffeemaster”. It’s a good idea to read the experience of others carefully before monkeying around inside the device. Old screws must often be limbered up a bit before you can closely adjust them. Don’t force them – they’ll break. When you make adjustments, don’t turn the screws more than about 5 minutes at the most, then see what happens. Your final adjustments will likely involve only a tiny tweak of the screws.
Remember that most of what you can read is helpful, but if you understand the explanation above, you’ll see advice based on misunderstandings too.
While the metal Coffeemasters don’t put on the same show a glass vacpot does, they have a show of their own. When the machine enters its bubbling phase, it bubbles loudly, trembles slightly, and if the air is right, sends a plume of steam straight up all the way to the ceiling. It looks like a little chrome bomb about to explode. It allows me to make 18 oz of excellent coffee, brewed automatically with the correct temperature and timing, in six minutes flat from plug-in to pour, with a beautifully designed and built machine that is more than a half century old, with many years more life left in it. Truly an impressive show indeed.