slatham2 Senior Member Joined: 18 Nov 2012 Posts: 1 Location: neu york Expertise: Just starting
Posted Sun Nov 18, 2012, 1:59pm Subject: Weighing Brew Water In Grams
I've been weighing my coffee dose for a while now, but not my water. For that I've been using ounces. My starting recipe has been the SCAA recommended 60 grams coffee per 1 Liter of water. But now I want to try weighing my water dosage as well.
I've heard different things about this, but my basic question is: when considering water weight in grams, are people usually talking about the weight of COLD water PRIOR to brewing??
So, for example, I heard Michael Phillips say that at Handsome they always recommend 15 grams of water for every 1 gram of coffee. But what exactly does that water measurement refer to? Because a.) water weighs differently when hot than it does when cold, and b.) the total dissolved solids present in the brewed coffee water make it weigh more than 'clean' water.
Or, another example: I read that the most recent US Brewer's Cup winner, Andy Sprenger, used a ratio of 12 grams of coffee per 205 grams of water.
But does that "205 grams of water" refer to COLD water BEFORE BREWING? HOT water BEFORE BREWING? Or HOT water AFTER BREWING?
I would think it refers to cold water before brewing, BUT! But, then why bother aiming for a certain finished scale reading when doing my pourover? Ya know what I mean? I mean, if that number refers to the measurement of COLD water in grams prior to brewing, and that's how much you are definitely going to use regardless of outcome, then what is the point of doing my pour over on a scale that measures the weight of the brewed coffee, which has a higher mass than the "clean" water, and which has a CHANGING mass throughout the brew process due to temperature fluctuation/drop?
Posted Sun Nov 18, 2012, 2:49pm Subject: Re: Weighing Brew Water In Grams
Hi.
Well. for starters, different respected coffee organisations seem to go for slightly different doses - generally either 55 or 60gm/litre. I work on 60 as it happens.
The grind level and/or brew time is likely to make more difference than any marginal mass difference between hot and cold water.
My understanding is that the recommendations are for the initial brewing water, rather than the resultant brew, simply because the latter would be difficult to standardise in any testing.
I know there are folk who swear they can tell the difference in tiny fractions of a gram when making espresso. I won't comment on that, but would suggest that such minor differences as you are pondering over are very likely to be masked by other variances in the pour-over/drip brewing process.
I think worrying about hot/cold/starting water volume/resultant brew volume isn't likely to make any discernable difference.
One thing that does matter, If you're using electric drip brewers that flash heat the water as it goes through, is that you should start with water that's about (I think) 16-18c for them to work properly.
Bottom line is, go with what your taste buds tell you. Everything else is just start point guidance or someone else's preference.
Posted Sun Nov 18, 2012, 6:03pm Subject: Re: Weighing Brew Water In Grams
Simplest answer is that yes the final weight is for hot water in the examples you cite. I tend to use a brew ratio of 17:1 i.e. 17g of brew temp water to each gram of coffee for pour over. This approximates to 60g/litre.
The weight of the dissolved solids is irrelevant. You zero/tare the scale before adding the water. The amount of coffee doesn't change. Although the coffee will retain water.
Using a ratio means you can ignore the fact that hot water is less dense than cold.
Either way it doesn't really matter since the error in using a measuring jug is likely to be as much of an issue as the difference in weight between hot and cold water.
Posted Mon Nov 19, 2012, 3:22pm Subject: Re: Weighing Brew Water In Grams
To answer slatham2's specific question: The specific volume in cubic ft/lb at 32F is 0.01602 (in fluid state) and at 212F is 0.01672 (in fluid state). The increase is only 4.37%. In that circumstance it doesn't matter much if you measure water cold or hot.
As it happens, one fluid oz of water weighs one oz avoirdupois at NTP. Similarly, one litre of water weighs 1 kg.
I never measure water in a measuring cup or other container with volume marks on it; I weigh it on a scale, usually in ounces. It's faster and MUCH more accurate.
I measure water in ounces and coffee in grams because those numbers are easier to remember and work with.
One last thing: When working with scales (and hoping for accuracy) never weigh something below the bottom 10% of the range. I have a 0 to 10 lb scale (with equivalent metric). I never try to weigh (say) 50 grams on that scale; it's asking too much of the instrument.
jpender Senior Member Joined: 11 Jul 2011 Posts: 400 Location: California Expertise: I like coffee
Grinder: Kyocera CM-50 Vac Pot: S/S Moka Pot Drip: Aeropress
Posted Mon Nov 19, 2012, 6:35pm Subject: Re: Weighing Brew Water In Grams
slatham2 Said:
I've heard different things about this, but my basic question is: when considering water weight in grams, are people usually talking about the weight of COLD water PRIOR to brewing??
So, for example, I heard Michael Phillips say that at Handsome they always recommend 15 grams of water for every 1 gram of coffee. But what exactly does that water measurement refer to? Because a.) water weighs differently when hot than it does when cold, and b.) the total dissolved solids present in the brewed coffee water make it weigh more than 'clean' water.
I may be misunderstanding your question. But if the recommendation is 15 grams of water it doesn't matter what temperature it is. Hot or cold, 15 grams is 15 grams. What changes with the temperature is the volume of 15 grams of water.
From a practical perspective, the amount of cold water measured before it is heated may not equal the hot water later simply because of evaporation. Spillage or water remaining in the pouring container can add to this.
jpender Senior Member Joined: 11 Jul 2011 Posts: 400 Location: California Expertise: I like coffee
Grinder: Kyocera CM-50 Vac Pot: S/S Moka Pot Drip: Aeropress
Posted Mon Nov 19, 2012, 6:41pm Subject: Re: Weighing Brew Water In Grams
JKalpin Said:
One last thing: When working with scales (and hoping for accuracy) never weigh something below the bottom 10% of the range. I have a 0 to 10 lb scale (with equivalent metric). I never try to weigh (say) 50 grams on that scale; it's asking too much of the instrument.
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