DoctorBeans Senior Member Joined: 29 Jan 2013 Posts: 5 Location: UK Expertise: I love coffee
Posted Tue Jan 29, 2013, 9:32am Subject: Strange problem with weighing water for V60
I am having problems with measuring the amount of water that goes through my V60.
I have a Jennings CJ-4000, on top of which I put a warm carafe, the V60, a washed filter, and 24 g of ground coffee. My goal is to get 390 g (or mL) of water going through in about 2.5 min. I then zero the scales and start pouring, slowly and in stages. The problem is that, after a couple of minutes, the readout on the scales actually starts decreasing quite significantly, even though I am still pouring water into the grounds. This makes it impossible to know how much water I am actually pouring over, and by the end I feel like I could be out by as much as 50-100 mL.
Has anybody seen this before? Does anybody know what's going on? Thanks.
Posted Tue Jan 29, 2013, 11:38am Subject: Re: Strange problem with weighing water for V60
DoctorBeans Said:
I am having problems with measuring the amount of water that goes through my V60.
I have a Jennings CJ-4000, on top of which I put a warm carafe, the V60, a washed filter, and 24 g of ground coffee. My goal is to get 390 g (or mL) of water going through in about 2.5 min. I then zero the scales and start pouring, slowly and in stages. The problem is that, after a couple of minutes, the readout on the scales actually starts decreasing quite significantly, even though I am still pouring water into the grounds. This makes it impossible to know how much water I am actually pouring over, and by the end I feel like I could be out by as much as 50-100 mL.
Has anybody seen this before? Does anybody know what's going on? Thanks.
Are you timing your pour with your cell phone nearby? Put it onto airplane mode and be sure to move other wireless devices away from it! See if that helps.
DoctorBeans Senior Member Joined: 29 Jan 2013 Posts: 5 Location: UK Expertise: I love coffee
Posted Tue Jan 29, 2013, 11:50am Subject: Re: Strange problem with weighing water for V60
Are you timing your pour with your cell phone nearby? Put it onto airplane mode and be sure to move other wireless devices away from it! See if that helps.
You know, I was indeed timing it with my cell phone. Tomorrow, when I try again, I'll take this into account and let you know how it goes. (It's too late in the day for another coffee now.)
yakster Senior Member Joined: 25 Feb 2009 Posts: 1,006 Location: San Jose, CA Expertise: I live coffee
Espresso: Gaggia Factory / La Peppina... Grinder: Vario / Kyocera Vac Pot: Yama 8 + Pyrex Lox-in Rod Drip: Brazen / Kalita / Chemex /... Roaster: Behmor
Posted Tue Jan 29, 2013, 2:53pm Subject: Re: Strange problem with weighing water for V60
I would also suggest testing your scale for heat sensitivity. Place your carafe full of hot water on the scale with something between the scale and the carafe to insulate the scale from the heat and make a measurement. Remove the heat insulator and place the carafe back on the scale with the insulator on top of the carafe this time and watch the scale to see if it weighs the same and if the weight changes as the scale heats up.
I picked up some cork coasters to see if this was happening with my American Weigh scales, but it did not appear to be an issue in my case.
I second this suggestion. I have a scale that is sensitive to heat. When I was weighing my espresso shot I was watching the weight change. Weird. Putting an insulator inbetween solved the problem.
Dana Leighton - Espresso hack and CoffeeGeek moderator
Posted Wed Jan 30, 2013, 11:50am Subject: Re: Strange problem with weighing water for V60
My American Weigh scales are DEFINITELY sensitive to temperature fluctuation.
I use a block of blueboard (rigid foam insulation) and all seems to be well. Place a hot cup of coffee directly on the metal plate, and the mass will drift many grams.
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"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
DoctorBeans Senior Member Joined: 29 Jan 2013 Posts: 5 Location: UK Expertise: I love coffee
Posted Thu Jan 31, 2013, 8:39am Subject: Re: Strange problem with weighing water for V60
I tried it today with a book underneath the carafe and I saw no drift in the weight measurement. I'll need to start looking for a more convenient way to insulate the carafe from the plate on the scales, however.
I'm a little surprised that I never saw any mention of this before (I did a lot of reading around before I decided on a set of scales). Is there a better sort of carafe to use to collect the coffee, i.e., one that's more insulated on its bottom? At the moment I'm using a stainless steel milk pitcher.
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