About 2 months ago our 10 year old Braun 12 cup machine finally died - and the quest began for a replacement. Braun now only does 10 cup machines, so our first misstep was to try a higher end Cusinart drip machine - the coffee was weak and sad. So I found this great site, read about a bazillion posts - and decided on the Newco OCS-12 pour over. My understanding is that it and the Technivorm are the superior drip makers mostly because of the right temperature and the fast brewtime.
We like our coffee strong and have access here in Portland to a great variety of high quality beans. But I do not find the OCS-12 any hotter, or anymore flavorful that that brewed by the old 12 cup Braun (using the same beans). But both are far better than anything else we've tried. Regardless, I was thrilled to find an adequate replacement - it is just as good as the Braun except for the overflow problem.
About every other time we brew, we get the dreaded overflow mess where the filter basket backs up and the whole mess comes out over the top. We bought the paper filters from Newco (Bunn I think), are only trying to brew 11 cups, clean everything well, and try not to overgrind. We have a 15 cup grinder and do like the coffee strong, but the grounds never sit dry in the filter past the halfway point or so of the paper (the basket is huge and looks like it would hold a whole lot of grounds easily). We've tried backing off the grind time until it is almost in chunks, and also have tried using less coffee - but we still get the overflow every couple of brews.
I read something about some "brew-through lids" causing backup problems, but we clean it and it looks fine. We also try to make sure that the little spring drain plug in the bottom of the filter basket is always clean and not in the "pause" position when we start the brewing process.
So my question is whether there are any known things more likely to cause this type of regular, but intermittment overflow?
My thinking is that I could remove the spring drain stopper apparatus and the lid to the thermos, and brew it for a while that way and see if it makes a difference. If yes, then I know the issue is something clogged in the mechanism of either the brew-through lid or the filter basket drain, if no, then I guess it has to be too much grounds or too finely ground. I'm assuming that even if I isolate it down to the mechanisms rather than user error on the coffee that I can't know whether it is the lid or the filter basket drain as they work together and you can't brew with just one or the other.
I could sure use some expert opinions. This is a great site!
Very curious problem, but here's a thought... What kind of grinder are you using? I wonder if the difference is due to powder in the grind. Fine powder may be produced at any grind setting depending on the blades or condition of the burrs. And it's the kind of thing that wouldn't be noticed in a slower brewing machine, but might cause overflow in a fast brew. The only easy way I can think to test this would be to grind the same beans with your normal grinder and also some other different kind of machine like one at a coffee roaster, cafe, grocery store, or friend's house.
I do a lot of manual-pour brewing through a couple of big Bunn baskets. And I'm unavoidably aware of differences between grinders, beans, the powder they produce and how fast the water will flow. I stand there and watch it drain! But I don't have any overflow problems unless I make a big mistake.
The grinder is a Hamilton Beach Custom Grind Deluxe 15 cup grinder. It is "supposed" to auto-grind and stop on its own, but it is touchy and you have to hold down the start button and then let off when you want to stop grinding. As I said, we backed way off on the grind time when we started to have this problem - probably grind for maybe 3 seconds now. Visually it doesn't look like there is a lot of powder, but I guess that is hard to see given that it is likely at the bottom. It didn't cause the Braun to overflow but as you say it didn't brew quite as fast.
I'm going to try my open brewing method (no top on thermos or drain plug) and see what happens. I'm sure I'll lose a little heat in the time it takes to brew, but I'll do anything to avoid cleaning up that overflow mess twice a week.
Blade grinders are very functional and inexpensive, but they're not normally good for a consistent grind particle size and low powder content. But still, this was only a wild guess and a comparison test is the only way I know to see if powder is the problem.
We've got an older cheap grinder that I'll try for awhile and see if it makes a difference. We bought the bigger one so that we could grind enough in one shot for our stronger coffee tastes, with the older one we had to do two loads for one brew.
Maybe a reverse test would be to purposely overgrind but go low on the amounts, brew it in the sink, and see if it overflows? Then go the other way, undergrind but overload the amount of grounds.
I don't know whether overflow is more related to too fine of grounds or too many grounds. The stuff I read seems to indicate that the most likely problem is too fine of grounds plugging up the works. The only other option I can think of is a defect in the brew through lid or basket drain.
Trouble is, it is hard to experiment at 6AM when you just want your coffee.
I'm a happy OCS-12 convert, and can share some thoughts that might help -
1) the filters that are supplied in the box with the new OCS-12 are 9.5" x 3", and you get about 30 of these with the brewer. When you order a box of 1,000 filters from Newco, however, the filters they provide are 8.5" x 3" -- and Newco insists that's all they sell for either the OCS-8 or OCS-12. Unfortunately, this means the filter is about half an inch lower around the sides when sitting in the filter basket. Quite possible that, depending on grind, humidity, moisture in the bean, recency of roast, and amount of grounds, you could wind up with "bloom" and an overflow. The first part of the solution would be to go online, and search for replacement filters for use with a Bunn brewer, sized as 9.5" x 3".
2) After having my OCS-12 a couple of days, I happily set up my brewer one morning, fired it up and went into my home office to check email. When I heard the familiar beeping about 7 minutes later, I came back to find coffee and ground all over the counter. After a bit of experimentation and research, I realized what was happening:
I had placed the empty filter into the basket, and then added the grounds to that. Apparently a few grounds wound up between the filter and the basket; they must have worked their way down under the filter and jammed up the drip-through valve. I played with this a bit, and discovered that it's actually pretty easy to jam the valve if grounds get into it. The solution, however, is quite simple, and I haven't had an overflow since switching to this:
I now set the filter down on the counter, and add the grounds just to the filter. Since it has a flat bottom, it sits quite happily, nice and flat on the counter. When the coffee is measured out, I carefully pick it up, using both hands so I can grab the top edge of the filter on two sides, and move it into the filter basket which I have sitting on the counter just a few inches away. This way, I *never* get grounds into the drip-through valve, and have never again had a flood.
BTW: it's very easy to clean out the drip-through valve -- it's a simple mechanism. You just have to be careful to not lose any of the small parts when you're working. I suggest you work over a large surface, like a table, with a good sized uncluttered area. Take a close look at the design of the drip-through valve first, to understand how it works. What you'll find is that the plunger is retained in the bottom of the filter basket by a tiny ring (I suspect is' silicone rubber), perhaps 1/4" in diameter. The stem of the plunger pokes through the middle of the rubbery ring -- it's a snug fit, and a small lip at the top of the plunger holds the ring onto the shaft. When then spring (on the same shaft, but underneath the filter basket) pushes the plunger down away from the basket, it winds up pulling the tiny rubbery ring (inside the filter basket) down, where is effectively acts as a drain plug.
I found it very easy to roll the ring off the top of the shaft, at which point the shaft is free to slide out of the bottom of the filter basket. The spring can then slide off the shaft, and you'll see that the valve mechanism is really just 3 parts. You can rinse them off, dry them and reassemble to the filter basket. I've only had to do that once, as reported above.
All in all, with the right filter (9.5" x 3") and filling the filter outside the basket before placing it in the basket (to avoid jamming the drip valve), you should be fine.
Brilliant! Thanks Jon. I'm almost certain that filling the filter outside of the basket will fix my problem. I'm sure I'm not very accurate in the early AM when I'm dumping my grounds into the filter, and when the filter is dry it always has a little "kink" in it when you try to get it to sit flat and even in the basket. Between that and the short filter top, I'd say the odds are good that at least a couple of grounds are getting under the filter every couple of times I brew - which would explain why my problem was intermittent and occured regardless of whether I used less grounds, less grinding time, etc.
I'll try it for a week and report back - but I think you hit the nail on the head.
I had a bunch of links where I was quoting the Bunn filter paper part # & size earlier (& Newco OEM OCS-8, -12 stock filter paper #'s), but not your link., so I ended up posting no links & got busy with other things..
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