Vac pot brewing temperature experiments
A discussion started in the "Favorite Brew Method" that led to this split off discussion.
A couple of the last comments:
Chris Dodson:
Okay so, I'm fairly certain that water will go up to the top part of a vac-pot without boiling. Does anyone have knowledge on this? Vac-pot has always been my #1, I'm just wondering.. Ya know...
Jason Haegar:
The water doesn't need to boil to go north, per se, but some water vapor is necessary to keep the pressure in the lower chamber.
So let's say that some water does boil, but the average temperature does not reach boiling. Your friend would approve. (I'm guessing that answers your question more easily)
Kayakman:
jason is correct... some but not much boiling
Brady:
Not to be contentious... but I was just able to send all the water in my 8-cup Yama north and keep it there without the lower chamber water ever going above 190 F (87 C). Only a couple of very tiny bubbles. Upper chamber water temp never topped 165 F (74 C). Darn near sea level here too.
This is why my first few vac-pot batches never came out very good... I was connecting the two chambers too soon and getting warmish water up north too quickly.
BTW... if you want to check the lower chamber water temp, do a run without the filter in place and stuff the thermometer stem down the tube. You can estimate temp pretty accurately by watching the size and bubbles, then apply your learnings to a real batch.
Jonathon Alrdrich:
Brady, I wonder if perhaps your problem may be putting too little water in the lower chamber vs. the capacity of the vac-pot. Seems like if proportion of water vs. available space is too low it would cause pressure to build up faster and send water up before it has reached the correct temperature because air heats up faster than water. Just a thought...
Brady:
Thanks, but this was an experiment to see how cool water could be and still be "sent northward"... in order to show what range of temperatures could be used to brew. So I intentionally did everything I could to keep the water cooler.
To get best control of temperature, I think its standard to leave the upper chamber detached until the water reaches the temperature you are looking for... then do your best to maintain that temp until the infusion in complete. This negates any impact of airspace. Good thinking though.
Keep it rolling guys, this is good stuff
-bry
A couple of the last comments:
Chris Dodson:
Okay so, I'm fairly certain that water will go up to the top part of a vac-pot without boiling. Does anyone have knowledge on this? Vac-pot has always been my #1, I'm just wondering.. Ya know...
Jason Haegar:
The water doesn't need to boil to go north, per se, but some water vapor is necessary to keep the pressure in the lower chamber.
So let's say that some water does boil, but the average temperature does not reach boiling. Your friend would approve. (I'm guessing that answers your question more easily)
Kayakman:
jason is correct... some but not much boiling
Brady:
Not to be contentious... but I was just able to send all the water in my 8-cup Yama north and keep it there without the lower chamber water ever going above 190 F (87 C). Only a couple of very tiny bubbles. Upper chamber water temp never topped 165 F (74 C). Darn near sea level here too.
This is why my first few vac-pot batches never came out very good... I was connecting the two chambers too soon and getting warmish water up north too quickly.
BTW... if you want to check the lower chamber water temp, do a run without the filter in place and stuff the thermometer stem down the tube. You can estimate temp pretty accurately by watching the size and bubbles, then apply your learnings to a real batch.
Jonathon Alrdrich:
Brady, I wonder if perhaps your problem may be putting too little water in the lower chamber vs. the capacity of the vac-pot. Seems like if proportion of water vs. available space is too low it would cause pressure to build up faster and send water up before it has reached the correct temperature because air heats up faster than water. Just a thought...
Brady:
Thanks, but this was an experiment to see how cool water could be and still be "sent northward"... in order to show what range of temperatures could be used to brew. So I intentionally did everything I could to keep the water cooler.
To get best control of temperature, I think its standard to leave the upper chamber detached until the water reaches the temperature you are looking for... then do your best to maintain that temp until the infusion in complete. This negates any impact of airspace. Good thinking though.
Keep it rolling guys, this is good stuff
-bry
Replies to This Discussion
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Permalink Reply by Bryan Wray on
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This is all good news to me as I never really did much research into vac pot brewing, I just did it. I would get some tasty brews and some down right disgusting ones, but I never did measure temperature (duh...).
I obviously was just sending the water up too soon. Thanks for the experiment Brady.
-bry -
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Permalink Reply by Jason Haeger on
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It's all about throttle control.
Adjust the flame until the water in the upper chamber stabilizes at the temp you want it. THEN add the coffee, stir gently to saturate, and do the rest normally.
One caveat. Make sure you keep the top on for long enough to force air out of the lower chamber, or the vacuum will not work properly at the draw down. (learned this vicariously through Chris O.) -
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Elaborate? I might be falling into that below 100 that we talked about the other day on chat...
-bry -
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Keep a digital thermometer in the water in the upper chamber. Adjust the flame heating the water (you do have an adjustable butane torch heater, right? If not, get one!) until the water in the upper chamber has stabilized at the desired brew temperature. Then add the ground coffee, stir to saturate. (if you are familiar with the varieties of pour techniques associated with pour-over brewing, then you should be able to watch the bloom color and so forth. But instead of pouring, you'll be stirring again. Too much agitation, however, will throw off the extraction and cause it to be over-extracted in a hurry.)
You know how complex brewing can be. This is just another avenue of execution.
side note:
If there is not enough time given to evacuate enough gas out of the lower chamber, the draw down will seem to stall due to a lack of vacuum. -
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Jason Haeger said:Keep a digital thermometer in the water in the upper chamber. Adjust the flame heating the water (you do have an adjustable butane torch heater, right? If not, get one!) until the water in the upper chamber has stabilized at the desired brew temperature. Then add the ground coffee, stir to saturate. (if you are familiar with the varieties of pour techniques associated with pour-over brewing, then you should be able to watch the bloom color and so forth. But instead of pouring, you'll be stirring again. Too much agitation, however, will throw off the extraction and cause it to be over-extracted in a hurry.)
You know how complex brewing can be. This is just another avenue of execution.
side note:
If there is not enough time given to evacuate enough gas out of the lower chamber, the draw down will seem to stall due to a lack of vacuum.
Okay... I got the first part the first time through, it was the second part I was confused on, but then you said, "stalling out" and I got exactly what you meant.
Thanks for the clarification either way.
(And nice profile pic change too... although I was a little confused for a second, you've had that other picture up for forever.)
-bry -
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I realized that my profile pic was a couple of years old. I actually looked younger in that pic. And I figured it would make sense if I used the same pic as I used here: http://espressotrainer.com/about/
We'll say that using a vac-pot is a whole new experience. You have control over the water, the burner, and everything in between. In addition to the agitation technique, saturation time, and the usual suspects with other brew methods. It's trickier, but it gives you more control over the variables. I quite like it. -
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Jason Haeger said:I realized that my profile pic was a couple of years old. I actually looked younger in that pic. And I figured it would make sense if I used the same pic as I used here: http://espressotrainer.com/about/
We'll say that using a vac-pot is a whole new experience. You have control over the water, the burner, and everything in between. In addition to the agitation technique, saturation time, and the usual suspects with other brew methods. It's trickier, but it gives you more control over the variables. I quite like it.
Agreed. It's a whole different animal, but my 6-7 months using them has been one hell of a learning experience for me.
-bry -
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I like to compare vac-pots to roasters. The larger it is, the less control you have. The smaller it is, the more control you have. (or something to that effect)
I rock a TCA-2 at home. (Thanks Barismo!) -
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Permalink Reply by Chris Dodson on
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I'm really glad this thread is still going. I'm too tired to add discussion right now though. Gotta be up at 6! I'm going to post a video soon of me doing a vac-pot. I'd love it if you all could critique and add thoughts. Thanks.
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Hey guys. Hope all of you are doing well!
I've been through 30 different angles for refining my syphon method since I got it 3 years ago.. Recently, I've been working on grind:extraction time stuff (finer grind, less time. coarser grind, more time.) I wish I could say that I've got my grind setting perfect, and I never have to move it. Alas, each and every coffee loves to be different! In my neck of the woods (Northern Virginia), I've motivated my peers to participate in "Year of the Kenya". I'm making it a point to try and evaluate every Kenyan possible.. in between drinking all of the other origins that catch my eye. I think we can all agree that Kenyan coffees are extremely recognizable in taste profile. This way, I can show my friends by example, how different origins/coffees actually taste *different*.
ANYWAY.
1. What are you guys doing for grind:extraction time stuff? Do you change it depending on the coffee? I find, I have to make 1-2 pots to dial in a new coffee.
2. Can you recommend any Kenyans to me for my project? I've already had every one Intelly has currently.
P.S. I know this is a thread about temperature control, but I felt this was a good place to go.
Thanks! -
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