Liquid weight vs volume

by **matt1203** on Fri Aug 26, 2011 9:05 pm

please bear with me if this is an old topic. I am new to the forum.

I follow roaster's recommendation trying to get

1.25 to 1.5 oz or 19g of espresso, but on my scale 1.5oz = to 39ml = 39g.

1g of liquid = 1oz?

what means extraction ratio?

by **yakster** on Fri Aug 26, 2011 9:15 pm

Avoid dealing in ounces. If you look in Wikipedia Here and Here, you'll see that the "ounce" is really many different systems of measurement, some volumetric and some mass based.

Pull your shot for 19 g of espresso.

The roaster is probably referencing a volumetric meaning of the word ounce and including measuring the height of the crema, but since crema varies, this is very imprecise. Volumetric measurements make it possible for those without scales to use shot glasses to estimate their shot, but since you have a scale, I'd stick to grams.

by **matt1203** on Fri Aug 26, 2011 9:42 pm

19g of espresso is only 0.75 oz though...

actually my scale when measure aqua only shows in ml. 1.5oz =39ml.

in order to get weight of g, I will have to press the button switch to regular weight measurement.

is it weight measurement are totally different than aqua? then my 39ml is not 39g.

by **boar_d_laze** on Fri Aug 26, 2011 9:46 pm

matt1203 wrote:I follow roaster's recommendation trying to get 1.25 to 1.5 oz or 19g of espresso, but on my scale 1.5oz = to 39ml = 39g. 1g of liquid = 1oz?

[W]hat means extraction ratio?

As Chris said, for these purposes, stick with mass and forget volume altogether. Not to worry, mass and weight are the same thing at the earth's surface, but saying "mass" makes you think you're smarter.

As weights, 19g is approximately equal to 2/3 of an ounce.

1g of liquid can never be 1 oz of liquid if the ounce is a measure of weight as there are (roughly) 28g per ounce (mass) If the ounce is a measure of volume, the liquid would be of very low density. 1g of water occupies 1ml (or 1cc) of volume, or approximately 1/30 of a fluid ounce.

The extraction ratio is the comparison of the weight of beans in a dose, compared to the weight of the resulting (straight) shot pulled. If the dose is 17g of beans and the extraction is 34g, the extraction ratio is 1:2 (note that the amounts and their ratio are quite common for a double normale).

Hope this clarifies,
BDL

by **entropyembrace** on Fri Aug 26, 2011 11:49 pm

matt1203 wrote:19g of espresso is only 0.75 oz though...

actually my scale when measure aqua only shows in ml. 1.5oz =39ml.

in order to get weight of g, I will have to press the button switch to regular weight measurement.

is it weight measurement are totally different than aqua? then my 39ml is not 39g.

It sounds like you're confusing yourself with different scale settings...

Just measure the shot with the regular weight measurement in g

by **allon** on Sat Aug 27, 2011 6:35 am

The confusion is between ounces and fluid ounces.

See http://en.wikipedia.org/wiki/Fluid_ounce

by HB on Sat Aug 27, 2011 8:34 am

matt1203 wrote:what means extraction ratio?

I think you mean the brewing ratio. In a nutshell, it's the ratio of weight of the coffee used to the weight of the resultant beverage.

by **sweaner** on Sat Aug 27, 2011 11:27 am

I wish more roasters would give their recommendations in weight, not fluid oz. X grams coffee- X temperature- X grams espresso. For 19g coffee I usually shoot for 19-28g espresso...or whatever YOU like.

by **matt1203** on Sat Aug 27, 2011 11:12 pm

boar_d_laze wrote: If the dose is 17g of beans and the extraction is 34g, the extraction ratio is 1:2 (note that the amounts and their ratio are quite common for a double normale).

Hope this clarifies,
BDL

I have 19g coffee made 39ml espresso which is exactly double normale..

what is you guys brewing ratio?

by **peter** on Sun Aug 28, 2011 12:39 am

matt1203 wrote:I have 19g coffee made 39ml espresso which is exactly double normale..

what is you guys brewing ratio?

If you want to discuss brewing ratio, both starting and ending measurements need to be in the same unit of measure.


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