HomeRoast Digest

Topic: Vac Pot Woes (29 msgs / 789 lines)
1) From: Jason Brooks
Some time ago, I picked up a Cory off ebay for a few bucks.  At first, I 
was able to get a good cup out of it.  But, life as it is, it's only 
rarely that I get to use it.  So Monday, being a day off, I pulled out 
my Cory for a pot.  I ground the beans (about 12 hour rest) in my Zass 
at about 1/2 a turn to 3/4 turn back from fully 'open'.  Let the water 
heat on the burner, and as it started to bubble, I placed the funnel on 
the top and seated it firmly, rod and grinds in place.  A few minutes, 
and I get the northward movement.  I let the water in the upper boil 
until the grinds are almost all mixed in and removed from heat, setting 
the assembly on a trivet.  Waiting, waiting, waiting.  Never any 
movement south.  Before, I've tried returning the vessel to the heat, 
but I can't get it to go south reliably. 
I'm wondering if it's my seal, but it seems to seat tightly.
Jason Brooks
Hanging Out in the Heart of VA,
Roasting in a Poppery, and soon arriving BBQ roasters,
Pressing in a Bodum Chambord and Columbia, 
Vaccing in a Cory Vac Pot,
Espresso from a Magister Home, and a Krups Gusto,
Drinking good coffee with anyone that arrives!

2) From: Aaron
If you have a good seal then the only other two things I can think of 
that it can really be is.   A.. your filter is really clogged and not 
letting the water/  coffee back down.    B. you are not letting it 
'boil' so that the air is driven off and the bottom chamber is filled 
with steam... which will condense when cooled.. and cause the vaccuum, 
which is what drags your coffee back down.  or....  Possibly your seal 
is not as tight as you would wish it to be?... I know a few walruses who 
said that too :)
Jason Brooks wrote:

3) From: Barry Luterman
If you are using a rod. Do not let the water boil violently at the end. a 
violent final push lifts the rod and allows the grinds under the rod 
resulting in a stall. Keep flame low. When all water goes North keep on low 
flame for 1 minute and then remove pot to trivet

4) From: Wandering Curmudgeon
Familiar ground to a lot of us.  I went through the same problem when
I first got my Cona-D.  It is important to get the grind right. It was
suggested that I get a commercial ground coffee and see if it stalled.
 And when it didn't  I set my grinder
 for the same size grind.  No further problems.
There are other problems that can cause a stall - water temperature is
another major contributor.   But for me its been grind size and dust
in the grind.
John - loving life in the slow lane
On 6/1/05, Jason Brooks  wrote:
ribes) go tohttp://sweetmarias.com/maillistinfo.html#personalsettings<Snip>

5) From: John Blumel
On Jun 1, 2005, at 8:52 pm, Jason Brooks wrote:
It could be the seal but there doesn't seem to be any way of testing  
that short of replacing the seal. See also, John Abbott's comments  
regarding grind.
However, it sounds as though you may be inserting the funnel too late  
and, possibly, removing from the heat too soon (I'm not clear on this  
last point from your description). The following instructions work  
fairly well and also help avoid the "jumping rod" problem mentioned  
by Barry Luterman. (If the filter is not a rod, simply ignore the  
parts about disturbing it since this isn't really an issue for  
plastic, cloth and paper vac pot filters.)
1. Put the water in the bowl and heat on medium high heat.
2. Meanwhile, insert the filter rod into the funnel, then grind your  
coffee and add it to the funnel, being careful not to disturb the  
filter rod as you do so.
3. When you start to see some water vapor escaping from the bowl  
(this is well before the water in the bowl boils), insert the funnel,  
again being careful not disturb the filter rod.
4. When the water begins to rise into the funnel, reduce the heat to  
medium low.
5. Once the water has finished rising into the funnel, reduce the  
heat to low. If the water left in the pot starts to boil, reduce the  
heat more or (with an electric stove) turn it off entirely. Ideally,  
you should have many small bubbles forming in and rising out of the  
water left in the bowl but never a full boil.
6. If the grounds are still floating, you may need to stir them  
under. Again be careful not to disturb the rod. You may wish to do  
this as the water is rising rather than waiting until it has finished  
7. After the desired steep time (I recommend ~45-90 seconds,  
depending on the grind and volume of coffee. I'm usually in the 45  
second range with cloth filters, around 60 with a glass rod in a Cona  
and a slightly coarser grind.) remove the pot from the heat and wait  
for the coffee to filter back into the bowl.
John Blumel

6) From: Brett Mason
Hi Jason,
Do your next vacpot with the upper bowl attached the whole time... If your=
seal is good, you will get the southbound train... And all will be well. 
Whoever suggested leaving it off apparently didn't read Cory's 
instructions... Or knows more than Cory who holds the patent....
We got an awfully spart list here... Mine never stalls....
On 6/1/05, Jason Brooks  wrote:
Brett Mason
_(( )_ Please don't spill the coffee!

7) From: Rick Copple
Jason Brooks wrote:
Hi Jason,
My first post to this list back in January of this year were concerning 
a Cory I bought off Ebay as well. I had lots of stall problems and still 
get them occasionally. It has a Cory glass rod, is all stainless steel, 
and is electric, but the pot is all one piece, can't take it off the 
"burner" and it shuts itself off. Luckily, it does generally bubble the 
coffee for about 1 to 1.5 minutes. It might help to go to the archives 
and check out that discussion (though there is a lot in there that is 
not related, at least directly, sort of took on a life of its own so 
thread is very long).
I also use a Zass, still do! :-)
Could potentially be the seal...that was part of the long extended 
discussion was how much a leaking seal might hinder the brew from going 
south even if there was enough of a seal to get it to go north. That it 
goes north indicates there is sufficient seal on it to get it up. How 
long does it generally take for it to go north?  What happens if you 
take some pot holders and apply a little pressure downwards for a 
bit...does the trip north speed up and then slow back down when you let 
up? If so, that might indicate a seal problem.
My problem wasn't the seal, however. Mine was a combo of things, the 
biggest being the grind setting as well as *how* I was grinding with the 
Now, you will probably have to experiment a bit cause I'm sure not even 
every Zass is exactly the same, but here is the setting that works best 
for me. I tend to come from the other direction than you do. I turn the 
dial until you can hardly move the burrs because they are as closed as 
they will get. Sometimes I have to turn the burrs a bit to get extra 
coffee bean pieces clear and then keep closing it. Once closed all the 
way, I then turn the dial 1 3/8ths out. Then, when you are grinding, 
make sure to either use your holding hand finger to rest on the dial or 
put something on it to keep it from drifting as you grind. Otherwise 
from my experience you can get a whole 1/8 to 1/4 turn to coarser during 
the grinding which will mess up the grind every time.
The other thing I discovered, at least with my open hopper Zass, is that 
the only support for the burr is the bracket that comes up to the top of 
the shaft close to where the turning handle is. What I was doing 
initially was to sit the Zass on a hard surface, a counter, and turn at 
a good pace. It was when I was over exaggerating the force of turning 
that I noticed the upper shaft rocking the whole burr assembly in the 
bracket. If it moved that much when really turning hard with some force, 
it probably moves a bit, though not real noticeable, when turning normally.
So, what I discovered was if I only turned it as fast as I needed to do 
so to grind the coffee and if I sat down and put it between my knees (to 
act as a shock absorber so that the upper bracket didn't take as much of 
the force of hitting bean resistance and breaking them up) that it 
greatly helped to reduce dust in the grind that significantly reduced 
stalls. Where I was getting them every time, now I only get the 
The other thing that could be a problem for you from what you said is 
when I put the top on generally some water comes up the funnel and pops 
the glass rod up. Essentially, as the top pot is put on and the seal 
takes hold, the rest of the pushing down actually is compressing the air 
trapped in the top of the pot and so pushes the water up the funnel to 
the top bowl. So, even though the water in the bottom pot is well below 
the neck of the pot, after I put the top on, there is generally some 
water sitting in the well where the glass rod goes. So, if you are 
putting the top on with the rod and coffee already in there, you are 
most likely causing the rod to pop up and get grinds under it, which as 
some people say, can cause stalls.
How I do it is I put the whole thing together, plug it in and let the 
water start heating up. Then I'll go sit down with the hopper full of 
beans in the Zass with a plastic cup I use because it has a wide mouth, 
and I grind the beans, usually dumping the grinds into the cup 3 times 
since the little box isn't big enough to hold all of it. By the time I'm 
finished with that, usually the water has just started to move upward. I 
usually throw my grinds in and then just let it do its thing. Most of 
the time I get some downward action. Sometimes it is a bit slower than I 
would like, but usually goes down.
Also, I've noticed that the type of roast and the roasting method can 
lend itself to more or less stalls. I've discovered that wok roasting 
seems to cause it to stall hardly ever, while popper roasting tends to 
create more stalls. Also, coffee roasted dark seems to create more 
stalls as well. I think the reason for both of these is oil. The more 
oil on/in the bean to make contact with the rest of the grind, it seems 
the more it tends to stick together and clog up at the filter. I've 
noticed wok roasted coffee seems to make the coffee beans come out dryer 
than when I roast them in the air popper. Possibly due to the difference 
in the length of time roasted, I don't know.
Then, in those times when it does stall or looks like it will take 
forever to go down, I have a long set of BBQ tongs that have the wire 
like end to them instead of solid metal "hands". If you are using a 
glass rod, I've found this thing can grab a hold of the top of the glass 
rod real nicely and firmly without much slippage. I will then take the 
tongs, grab the top of the glass rod, and gently move it back and forth 
a bit. Watch for results, when you see the coffee starting to go down at 
a good pace, stop and let it go on its own.
If that doesn't do the trick, slowly, so very slowly pull up on the rod 
a bit. The vacuum will resist the pull, but do it slowly for every once 
in a while I catch it without much vacuum and then you risk pulling the 
rod too far out and dumping grinds into the bottom. I don't ever get to 
pulling up real hard, I use just enough pressure upward and moving the 
rod from side to side that the water begins to go south. Generally I'll 
stop occasionally to see if it will take off on its own, sometimes it 
does, sometimes it doesn't. If not, I'll keep pulling and moving until 
it either takes off on its own or gets to the bottom. Be sure to stop 
before the water is all the way out just so when the vacuum is relieved 
you don't inadvertently pull the rod out.
When using air roasted beans, I tend to have stalls about 20-25% of the 
time depending on roast level and sometimes certain beans are more 
prone, I assume because of a higher oil content in the bean. With my wok 
beans, I hardly ever have a stall.
Now that I think about it, I believe what happens is the wok roast 
produce a harder "skin" on the roasted bean and so less dust is created 
in grinding, but an air roasted bean seems to be more easily crushable 
and so the result of grinding causes it to dust up more. That might be 
the explanation there.
I had to do several experiments to find the grind that worked for me. If 
the one I recommended doesn't do the trick, you might start with 1 full 
turn from closed, then move at 1/8th increments until you find the grind 
size that works best for you. Maybe get some Folders whole bean coffee 
to test this out on something cheap that you don't mind throwing away.
Rick Copple
Marble Falls, TX

8) From: Jason Brooks
Thanks for all the input.  I'll digest and try this weekend on the gas
grill burner.  But after putting my Cory up last night, I'm suspecting my
seal has gone south.  The funnel was hand washed and had been sitting out.
 The carafe was in the dishwasher.  I seated the funnel in the carafe to
put away, and there is almost no friction in the fit.  If I recall
correctly, when I first received it, I could just about pick up the whole
unit with the funnel seated; there's no hope of that now.  What I'm
wondering is if, in the presence of heat, would the seal be better?  I
guess I'll find out in a couple of days.  Otherwise, I'll look for a new
BTW, would a D-9 (I think) match with one of the seal from restaurant supply?
Thanks again,

9) From: David B. Westebbe
If there is vacuum in the lowerpot, you will feel it when you remove the
upper pot.
If there is none, then the seal is likely shot.

10) From: Brett Mason
Y0u need a new seal - they're not that expensive from food service 
On 6/2/05, David B. Westebbe  wrote:
Brett Mason
_(( )_ Please don't spill the coffee!

11) From: John Blumel
On Jun 1, 2005, at 11:55 pm, Brett Mason wrote:
The reason for leaving the funnel off until the water in the bowl  
begins to steam is to minimize the extraction time. Otherwise, you  
get a longish period where water rises into the bowl and mixes with  
the grounds while the bowl heats up.
This is really no different than preheating water before adding it to  
the bowl.
The instructions on many vac pots say to insert the funnel before  
beginning to heat water in the bowl but this is simply for operator  
convenience, not because it is the optimal method of using a vac pot.
John Blumel

12) From: Jason Brooks
Is the single one they sell kosher for a wide mouthed Cory?  I'm assuming
wide b/c I've seen some that look like a mouth diameter of an inch or two.
 Mine's between 3 and 4 inches wide.

13) From: Gary Townsend
Just to simplify things a little, as I am a firm believer in the KISS
method, I'll add my observations. ;-)
1) What goes up, must come down. 
Assemble the upper and lower bowls. Add water. If it does not go back
down, then the seal is probably good enough!
2) Fill the lower globe with the proper amount of water, install
filter, and re-assemble the 2 globes. Apply heat, and observe water.
When it makes the trip up, cut the heat back some, and keep it 'up'
for 2 minutes. Remove from heat, and observe the water going back into
the lower globe. In this case, fast is good, and a quick return tells
you that your seal is in good shape.
3) If everything is good to go, at this point, it's time to add your
grounds. Start off with a 'coarse' setting. The same as when making a
drip pot. You can adjust this setting later, but for now, you are
trouble shooting. A can of "FoalTurds" or any 'disposable' can of
coffee will do. Save the 'good stuff' for later on, when you get the
process down pat.
* I have 2 antiques, a Silex and a Hill Shaw with 50+ year old seals.
They both will produce a great cup of vac'ed coffee. For me, clean and
dry deals are the ticket. Some folks wet the seals and it works well
for them. Whenever I wet the seals on these pots, I get a stall. So, I
keep the seals dry. And I twist the globes with firm pressure, to
minimize a chance of an air leak.
I finally broke down, and bought a Yama pot, brand new for $20. on
E-bay. I use it 3 -5 X a week, so it has a spot on my kitchen counter,
right next to my espresso machine ;-) No more sealing problems.
4) The filter. I have used a Cory rod, and I like it. I also have the
cloth filter, and after 3 months, it still works fine. I clean it
immediately after a brew, and keep it wet, in a class cup, in the
refrigerator. You are less likely to stall with the cloth filter, but
if you grind fine enough, you will stall it!
5) I assemble everything, and start the process of heating, then I
wait until the water is up. Then I cut the heat back, and then add the
grounds. Start time. Give it a little stir. At 90 seconds, I remove
from heat. I watch the pull, and I am aiming for a total extraction
time of 4 minutes, + - 15 seconds. I separate the globes, and rinse
out the top globe and filter in the sink. Clean, rinse, dry, and
store. That takes about a minute or 2. Then, pour 2 large cups of
coffee, then rinse, clean and dry off the lower globe. Done. Now I'll
go enjoy a great cup of coffee, and watch the squirrels steal food
from the bird feeder.
Good luck, and IMO, vac pot coffee is worth the extra effort. I
totally enjoyed Tom's Monkey Blend yesterday on a 2 hour drive to
Kansas City Airport to pick up my 20 year old daughter. She took a big
sip and told me that "It's really good" and that's all the
encouragement that I need :-)

14) From: Jason Brooks
Thanks Gary.  I'll have to try that.  And a few year's ago, I could've
gotten to the KC airport in about 4 hours ;-)!  Still miss St Louis on
occasion, but not enough to give up the quiet life in the relative

15) From: Brett Mason
The reason for putting the bowl back on is that is the method recommended b=
Cory. Who knows, maybe, just maybe, they know their product.
This is not necessarily a lifetime commitment. You are not breaking vows if=
you try it once, then go to another method. 4-5 tries, and you just might=
learn something.
John, give it a rest and let the poor guy do what was designated in the 
manual. Or did you write the manual, and as such are speaking on the basis=
of what you know when you wrote the original manual.
Did Mr. Cory pay you for the patent, or did he think this up without you?
Sometimes the4 scientists are so darned arcane it drivesw me nuts....
RTFM stands for Read The Manual. It's at least worth one try...
On 6/2/05, John Blumel  wrote:
Brett Mason
_(( )_ Please don't spill the coffee!

16) From: Brett Mason
Yes. It helped when I boiled mine, then put it on the upper bowl (funnel),=
and placede the upper bowl onto the lower bowl, and let it stay that way fo=
a day. Now it's a perfect fit....
On 6/2/05, Jason Brooks  wrote:
Brett Mason
_(( )_ Please don't spill the coffee!

17) From: Wandering Curmudgeon
On 6/3/05, Brett Mason  wrote:
I find it odd that you would single out John's post after Rick Copples
classic 8 page post.  The reason I fastened onto this reply was that
initially I thought it was my post that you were responding to - but
then noted the post from JB attached.
There are a lot of things that can go wrong with a vacuum brew and I
think both Rick and John were trying to graphically take Jason through
the process, since he yelled for help.
In honor of the occasion I fired up my Cona-D this morning and brewed
some La Pluma which I'm now swilling as I type.  There's plenty left -
come on over!
John - loving life in the slow lane

18) From: Brett Mason
I'm on my way over.... After I responded to John's, I did see Rick's post,=
and felt a little silly.
And I do understand John's intent to teach/share and help. I shouldn't have=
been so directly confrontational of John (sorry John).
I have done hundreds of Cory VacPot brews, and also have my set of 
guidelines, including following the manual. I am still a believer in new 
seals, getting them in and working. I am also a believer in good grinders,=
like my Cory grinder, Zass, and now my Rocky too.
I am pretty certain the coffee won't go wrong by putting the top globe onto=
the bottom before heating, and I KNOW that following this will ensure the=
steam escapes, and a proper vacuum will becreated after removal from heat.=
There is a certain risk that without following this course an appropriate=
vacuum may not be achieved if too much time transpires between heating, 
removal from heat, and the addition of the upper globe...
Still reading the manual,
Zassman still
On 6/3/05, Wandering Curmudgeon  wrote:
Brett Mason
_(( )_ Please don't spill the coffee!

19) From: Jason Brooks
Sorry to be so literal, but is there an extant cory manual out there? 

20) From: Rich Adams
http://baharris.org/coffee/used to have copies of all/most of the Cory 
manuals, can't seem to find them now.
Rich Adams

21) From: Rich Adams
Found some....(cory instructions)http://www.oldcoffeeroasters.com/new_page_1.htm

22) From: John Blumel
On Jun 3, 2005, at 2:42 am, Brett Mason wrote:
Right, because no one ever finds, with any product, that the  
manufacturers instructions don't work as well as some alternative  
method. All products are perfect as built and all instructions are  
perfect as written by the manufacturer.
So, everyone, please stop tinkering with your roasters, espresso  
machines, etc. They aren't going to work as well if you deviate from  
the original design or instructions. And please stop trying to build  
roasters out of things that weren't designed to be roasters. It  
simply won't work.
John Blumel

23) From: Jason Brooks
    Thanks for that.  According to the Cory docs, I'm likely getting the
problem because the trip north is too rapid.  As someone earlier
suggested, the rod shouldn't wiggle as the water travels north.  The
Cory doc said it should move up slowly.  Slow is not the description
of using the Cory 'widow maker' stove.  So, out to the gas grill I
will go, likely tomorrow AM.  Might do some testing tonight without
any grind to test the vacuum.
Thanks for all the eyes, ears and fingers helping me find a resolution to
my stall.  You are all gerat!

24) From: Gary Townsend
 Jason Brooks  wrote:
 Found some....(cory instructions)
http://www.oldcoffeeroasters.com/new_page_1.htmGood link! 
I think I'd like a copy of them, framed, next to my dinosaur's (
Silex, Hill Shaw vac pot's) ...for nostalgic value. Hmmm might see if
my photo editor is up to the task!

25) From: Rich Adams

26) From: Jason Brooks
Thanks to everyone for their insights and links.  I've synthesized most 
of what was sent out.  Here's what I did and found on Saturday morning.
First, I took the vac pot with filter out to the grill and put it on the 
side burner.  As the water headed north, I was noticing some bubbling in 
one spot around the seal.  Got a pot holder, adjusted.  After the trip 
north was complete, I killed the heat and went inside for something.  
Back out in a few minutes, and the funnel was empty!  So, I reseated the 
funnel again, trying to insure it was seated well.  With only water, I 
fired up the burner again.  North was fine, south as well.  So, now for 
some beans.
I added what was probably a bit too much Kenya AA Ithima.  I ground it 
in my Zass 169 about 1 1/2 turns back from touching.  Carefully dumped 
them into the funnel.  Placed on the burner, careful this time not to 
let the upper chamber boil.  I used a spoon to insure the grounds were 
fully wet.  As the water headed north, I slowly reduced the heat to 
prevent any boiling.  Removed from heat, and in four or so minutes, I 
had a completely evacuated funnel.
So, with that, here's what I going to change:
1)  Forget the widow maker stove that came with the Cory.  It can't heat 
the water with out boiling the funnel water and upsetting the rod, 
allowing grounds to get beneath and stall the brew.
2)  Greater care with the grind.
3)  Slowly, oh so slowly allow the water to head north.
4)  I'm going to try Rick's suggestion for a wok roast producing a 
better bean for vac pots.
5)  Monitor the seal; it still may be going.
Thanks again, all.  I think I might be on my way to vac pot heaven!
BTW, the Kenya was wonderful.  At only 12 hours rest, it was wonderfully 
sweet and mildly fruity!
Jason Brooks
Hanging Out in the Heart of VA,
Roasting in a Poppery, and soon arriving BBQ roasters,
Pressing in a Bodum Chambord and Columbia, 
Vaccing in a Cory Vac Pot,
Espresso from a Magister Home, and a Krups Gusto,
Drinking good coffee with anyone that arrives!

27) From: John Blumel
On Jun 5, 2005, at 9:18 pm, Jason Brooks wrote:
Definitely an improvement, although, I think you might have been a  
bit too gentle with it.
You don't have to worry about the water in the funnel "boiling" and  
you should get some bubbling action up there as air and steam are  
forced out of the bowl. It's just the first big pop that you need to  
avoid with the rods. Once you get a steady air evacuation going, the  
upward pressure of the air/vapor will keep the grounds from falling  
under the rod. It's good to have a very light boil or simmer in the  
bowl while the water is up in the funnel -- many small bubbles rising  
rapidly -- just not a full, roiling boil.
Just a touch more heat and hold it up in the funnel for 60-90 seconds  
(depending on grind) and you should get a faster return from the  
funnel back to the bowl, which should give you a better cup. But it's  
best to make small adjustments to your technique until you find just  
the right balance.
John Blumel

28) From: David B. Westebbe
 For me, clean and dry deals are the ticket. Some 
Wow.  I use narrow-neck Silexes from 1938.  All I do is plop the top
onto the bottom and don't worry about it.  Sometimes the seal is dry,
and sometimes it is wet from being washed.
I haven't noticed a difference.

29) From: Gary Townsend
I *think* that a coarser grind is much less likely to stall, and when
I use my older vacpot's with the original 50 yr + seals, I normally
use a coarser grind. I use a modern Yama pot, and I *think* that using
a finer grind tastes better. But the older glass vacpot's have a lot
of style, and it's nice to restore one to working order.
Lately, I've really gotten hooked on Les's Mare blend..50/50
Harar-Sumatra, in a vacpot, with 3 days rest it's just a really great
cup of coffee!

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