replicnt6 Senior Member Joined: 29 Mar 2008 Posts: 2 Location: Arlington Expertise: I love coffee
Posted Sat Mar 29, 2008, 1:59pm Subject: Vac-pot glass filter technique (where am I going wrong?)
I have tried the following combinations of vac-pot and glass filter: Recent Yama 5-cup w/new cona glass filter, New Hario Deco 5-cup w/new cona glass and New Hario Deco 5-cup w/nos cory glass filter. In every attempt I've made, the draw-down stalls terribly.
Here's my technique: boil 18oz water, but in lower bowl, put on heat, insert top. Wait for top full, add 36g medium grind grounds stir, wait 1 min, take off heat. I try tapping the glass filter. I always end up with a near perfect seal of the filter against the siphon, making it virtually impossible to move. I get slow bubbling down the siphon. It might draw down after 1/2 HOUR - 1 HOUR if I waited that long. Instead I break the seal between the siphon and the pot for fear that the pot will break. I give it several minutes, though.
I'm using a fairly medium grind.
What am I doing wrong? Do I need a finer grind? A coarser grind? Is there some trick?
Posted Sat Mar 29, 2008, 2:26pm Subject: Re: Vac-pot glass filter technique (where am I going wrong?)
replicnt6 Said:
I have tried the following combinations of vac-pot and glass filter: Recent Yama 5-cup w/new cona glass filter, New Hario Deco 5-cup w/new cona glass and New Hario Deco 5-cup w/nos cory glass filter. In every attempt I've made, the draw-down stalls terribly.
Here's my technique: boil 18oz water, but in lower bowl, put on heat, insert top. Wait for top full, add 36g medium grind grounds stir, wait 1 min, take off heat. I try tapping the glass filter. I always end up with a near perfect seal of the filter against the siphon, making it virtually impossible to move. I get slow bubbling down the siphon. It might draw down after 1/2 HOUR - 1 HOUR if I waited that long. Instead I break the seal between the siphon and the pot for fear that the pot will break. I give it several minutes, though.
I'm using a fairly medium grind.
What am I doing wrong? Do I need a finer grind? A coarser grind? Is there some trick?
The Yama's gasket system is so good, one should NEVER get a stall...my suggestion is allow a longer brew time....2 minutes... don't wait for all the water to go "North before loading in the grind...when water has risen 1/2 way, slowly pour the grind in.) By the way, get the water to 190f, no hotter when you place the upper globe on......do not boil, or your brew...if it ever DOES work...lol...will be bitter. When you remove the unit from stove at 2 minutes, place on a cool surface, wet a paper towel with cool water, and softly rub the moistened cool towel across the surface of the UPPER globe. This will help facilitate drop down. Don't forget to brew with the top on. HERE'S A GOOD IDEA...LOSE the cloth filter assembly , and, if it filts, use the Cona glass in the Yama...better still, go on ebaY, and bid on a SILEX LOX-IN glass filter (it has the chain with hook, like your Yama.....if you can't find one, just get the standard CORY GLASS FILTER...and ALWAYS BREW A FULL POT. Let us know how it goes...If your not, i'll be glad to take your Hario's off your hands (cheply, of course
EDIT...geesh...sorry, I misread your topic...glass filter...what a dope (me) What I said, those is proven vac pot technique...I NEVER have stalled pots with new vacs...only occasionally with old vintage ones.
Posted Sat Mar 29, 2008, 3:02pm Subject: Re: Vac-pot glass filter technique (where am I going wrong?)
I'm a relative vacpot newbie, and I've never had a stalled pot, so unfortunately I can't give you a definite answer. Before buying my vacpot I did A LOT of searches of this forum and read A LOT of posts, and no one seems to really know for sure what causes a pot to stall. Some people rarely or never get stalled pots and some people seem to almost always get them. It remains one of life's mysteries.
I've used my 5 cup Yama with the Cona rod (although I most often use a Bodum Santos plastic disk, which works great and fits the Yama perfectly), just like you have and never had a stall, but my technique is very similar to yours.
The only thing I do differently is preheating the water before putting the top on (you don't mention how long you heat the water before putting on the top). I have experimented with adding the grounds to the top before putting it on and after the water has started to rise (I don't wait until it is all up), and found no significant difference (although adding after allows you to control the brew time more precisely).
One of my unproven THEORIES about why pots stall is that some grinds slip under the filter while the water is up, but before the draw down. Then the contact between the filter and the pot is disrupted and instead of the grounds being kept OUTSIDE the contact point, they build up AT/IN the contact point and create a blockage.
I think this is more likely to happen when the heat level is uneven. While the water is up top, water/steam pressure lifts the filter a little. If the heat/pressure drops too low at any point, the force keeping the grounds from settling against the filter is reduced and grounds are more likely to slip into the gap. I also think this is more likely if the top is filled with grounds before being attached since the grounds start out resting against the filter, but you are not doing this.
However, I also think that disturbing the filter while adding coffee and/or stirring can have the same effect, and this may be the cause of your problem. Excessive heat that causes violent bubbling can also rattle the glass filter rod and mess with the contact point. One of the reasons I like the Santos filter is that it is anchored to the siphon tube by a spring and will not be dislodged when adding coffee, stirring, or by bubbling.
I have also never heard of a stalled pot using the Yama/Hario cloth filter or the Hario paper filter holder (I just got the Hario paper filter holder, but have not tried it yet). These filters allow liquid to pass right through them, so the contact point between the filter and the glass is not a factor. If you don't want your brew actually passing through a filter the Santos disk might be an option to try.
In the meantime, try some pots where you do not stir at all and try experimenting with different heat levels, as well as adding the grounds to the top before attachment, or earlier after the water has started to rise. Then, if you don't get a stall, you will have a better idea of what the problem might be.
Once again, my stalled pot theory is totally speculative so I may be completely wrong, but I hope it helps.
Just because it happened to you doesn't make it interesting.
In theory, there is no difference between theory and practice. In practice, there is.
Posted Sun Mar 30, 2008, 5:23am Subject: Re: Vac-pot glass filter technique (where am I going wrong?)
I struggled with the Cona glass rod, too. I've discovered that I never want to touch the rod after the water starts coming up, and that too much agitation when the water finishes coming up will stall things later on.
Even so, the movement of coffee from the top globe to the bottom takes considerably longer with the glass rod than with the cloth filter -- maybe twice as long, maybe not quite -- but if it takes more than a few minutes with the glass rod on the five-cup there's a real problem.
I'd start with the two suggestions here, then try a slightly coarser grind with a longer brew time. My grind is roughly the same as for drip and I let it go 3 1/2 minutes up top before taking it off the heat. The advice elsewhere in this thread about keeping the water at 190 or so and no higher before laying in the grounds is also very good. It's easy for the temperature to get away from you, and I find that if the temperature hits 200 (and it always goes up after putting in the coffee), it's going to taste burnt.
I've never had the nerve to put a wet towel anywhere near my Yama, but I've seen it done on a Hario (which I think is made of Pyrex) in a YouTube video.
replicnt6 Senior Member Joined: 29 Mar 2008 Posts: 2 Location: Arlington Expertise: I love coffee
Posted Sun Apr 13, 2008, 2:47pm Subject: Re: Vac-pot glass filter technique (where am I going wrong?)
So I had my first success with a glass filter today (Cory rod in Hario vac-pot) (I've only been experimenting on weekends when I have the time to deal with a stalled pot. During the week, I've been using the paper filters).
I believe I have isolated my problem to something I neglected to mention in my original post: After removing heat, I had been stirring quickly to gently cool the slurry. Today, I didn't do this. The draw-down was lovely.
Theory: stirring distributed the grounds through the slurry leading to a lot of grounds accumulating at the filter early in the draw-down. Without stirring, the grounds tend to float, leaving the ground accumulation at the filter to the end of the draw-down.
Thanks everyone for your help and suggestions. Hopefully, with this change, I'll have more success.
scpizza Senior Member Joined: 14 Apr 2008 Posts: 24 Expertise: I like coffee
Posted Mon Apr 14, 2008, 7:04pm Subject: Re: Vac-pot glass filter technique (where am I going wrong?)
After many Yama Vac pots using the cloth filter, I just tried my first pot using the Cona glass rod. The results were really impressive. The coffee tasted categorically better - richer, fuller, buttery. Maybe it's just psychological, but it really seemed to taste like I was getting the coffee oils in this pot. Prior pots with the cloth filter tasted more watery and plain. To be fair, I should do some back to back pots each way and compare.
The glass rod rattles around a bit when bubbles are coming up. Unlike with the cloth filter which is perfect, when the coffee first breaks down into the bottom using the glass rod I noticed a bit of grinds going with it. Nothing too crazy though, just need to leave a tad of dregs behind when pouring to the bottom.
Posted Wed Apr 16, 2008, 9:41am Subject: Re: Vac-pot glass filter technique (where am I going wrong?)
replicnt6 Said:
Theory: stirring distributed the grounds through the slurry leading to a lot of grounds accumulating at the filter early in the draw-down. Without stirring, the grounds tend to float, leaving the ground accumulation at the filter to the end of the draw-down.
I'll have to test this theory. I've tried a Cona rod on my Yama three times now; twice was a full stall that I thought would implode the globe, and last night I got a very slow drawdown, but not a complete stall. I keep using a coarser grind each time, and I usually stir the grounds a couple times during the process, including a quick stir before I pull it from the heat. I've also been using beans that have a lot of chaff, so I think the chaff is getting stuck on the glass filter and causing havoc.
Posted Wed Apr 16, 2008, 9:53am Subject: Re: Vac-pot glass filter technique (where am I going wrong?)
Jeebs Said:
I'll have to test this theory. I've tried a Cona rod on my Yama three times now; twice was a full stall that I thought would implode the globe, and last night I got a very slow drawdown, but not a complete stall. I keep using a coarser grind each time, and I usually stir the grounds a couple times during the process, including a quick stir before I pull it from the heat.
Don't stir at the end of the process, that's what is causing the problem!
replicnt6 Said:
Theory: stirring distributed the grounds through the slurry leading to a lot of grounds accumulating at the filter early in the draw-down. Without stirring, the grounds tend to float, leaving the ground accumulation at the filter to the end of the draw-down.
Don't stir the coffee at the end of the process, (stir of course to wet/mix the grinds) the coffee will follow the centrifugal vortex to the center bottom of the top pots outlet & collect a bigger than normal pile at the rod & you don't want that disturbed filter bed.
Let the coffee settle naturally & it will form a perfect filter pack filtering upon itself., coarsest at the bottom nearest the rod.., & then with progressively finer grind particles upwards. I rarely (99% of the time) have a problem. {;-)
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