# David Schomer's ounces



## Phil104 (Apr 15, 2014)

Once again I have spent a happy few days (that's what it seems like) reading threads on the forum that debate fluid ounces and weight. I'm very content working with grams. This afternoon I started reading David Schomer's book. I was interested in his mix 'n' match of 'about' 17gms in (although he also suggests 16 gms) and 1.5 ounces out. I assume that he means fluid ounces. Anyway, I wondered what he means by 1.5 ounces so started to read about the complexities of converting fluid ounces to gms (on account of needing to know the density of the liquid) and, as a true believer, studying forum threads where, unusually, I can't quite find the answer (or even multiple answers) to my Schomer question.

So, simply out of academic interest, when Schomer says 1.5 ounces what does he mean in grams?

Also out of interest, is it right that different coffee beans will produce liquid of different densities? So the 1.5 ounces he quotes might be bean dependent?

I haven't read all of his book so the answers may or may not be there....


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## Mrboots2u (May 10, 2013)

Here one reason why you should use weight in and weight out ,as a more accurate measurement and why I can't see how 1.5 ounces can be a set amount of grams

If you pull a shot of beans roasted 5 days ago to 30g

Then pull a shot of same bean 15 days later again to 30g

The fresher beans will produce more co2 during extraction than the older ones

And therefore the drink have a larger crema relative to their weight ( copyright scott rao ) and be a bigger volume

Again some blends will naturally produce a bigger volume due to robusta giving a bigger crema .....

This is why weight in and volume out isn't as accurate as weight in weight out .

So doesn't answer your question but even the same beans will in theory produce different volumes etc...

How can 1. 5 ounces as be a consistent weight given the above even for the same bean ?


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## Phil104 (Apr 15, 2014)

Thank you Mrboots. It reinforces the view that going by fluid ounces is unreliable (so I wonder why David Schomer relies on it - unless he has changed to weight). Also, does it mean that the same beans will produce different densities of liquid at various points in their roasted life?


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## DavecUK (Aug 6, 2013)

You don't measure to level of crema, just liquid...volume and weight are pretty similar e.g. 40ml weight about 40g. The dissolved coffee solids doesn't add hardly any weight. I've checked it before using measured volumes (drawn by a syringe) and weighed them. I know people on the forum have said (when I last posted this), that there was 4g extra eight for 40ml, it weight 44g, this is absolutely NOT what I have found..ever. So I think volume can be a very good guide. Besides, you choose when you stop the shot visually anyway.

I simply think all this weighing the shot is nonsense.


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## Mrboots2u (May 10, 2013)

And policemen are getting younger too

Money was also better in pounds and shillings


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## Phil104 (Apr 15, 2014)

DavecUK said:


> You don't measure to level of crema...


 It's not clear what Schomer includes in his 1.5 ozs - the photographs suggest that it includes the crema but he also makes the same point about visually checking (and of course time). I'd be interested to experiment with volume and see the difference.


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## Mrboots2u (May 10, 2013)

Phil104 said:


> It's not clear what Schomer includes in his 1.5 ozs - the photographs suggest that it includes the crema but he also makes the same point about visually checking (and of course time). I'd be interested to experiment with volume and see the difference.


Hence it not being amazingly accurate way of say even describing or comparing shots between baristas , shops , other people .

Where are you measuring it crema not crema etc ......


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## AndyS (May 12, 2012)

DavecUK said:


> I simply think all this weighing the shot is nonsense.


Relax, Dave, no one is forcing you to weigh your espresso shots. ;-)


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## DavecUK (Aug 6, 2013)

AndyS said:


> Relax, Dave, no one is forcing you to weigh your espresso shots. ;-)


I am relaxed, I just think its nonsense. I also don't feel forced to weight my shots....sometimes though I'm filled with wonderment with the faffing about to make an espresso. I have seen a few Vids on the web (especially with hi end hand grinders), where 3 minutes in (or more) and the portafilter isn't even locked home!


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## Mrboots2u (May 10, 2013)

Dave -Not really helping the OPs questions though is it ?


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## DavecUK (Aug 6, 2013)

Mrboots2u said:


> Dave -Not really helping the OPs questions though is it ?


I think I posted this earlier

You don't measure to level of crema, just liquid...volume and weight are pretty similar e.g. 40ml weight about 40g. The dissolved coffee solids doesn't add hardly any weight. I've checked it before using measured volumes (drawn by a syringe) and weighed them. I know people on the forum have said (when I last posted this), that there was 4g extra eight for 40ml, it weight 44g, this is absolutely NOT what I have found..ever. So I think volume can be a very good guide. Besides, you choose when you stop the shot visually anyway.

I simply think all this weighing the shot is nonsense.

That pretty much seems to help the OPs questions, the rest is forum discussion fowllowing on, moderate it out if you think it's inappropriate.. or tell me what you think I should post?


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## Mrboots2u (May 10, 2013)

Don't need to mod it Dave , thanks for suggesting it though .

Just wanted to leave some room for answering the OPs questions before it becomes a debate on the nature or value of weighing shots etc.

I Ve seen threads like this on other forums become derailed whenever weighing or refracting or vst get mentioned

All opinion welcome though and constructive feedback is helpful


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## Mrboots2u (May 10, 2013)

Phil104 said:


> Thank you Mrboots. It reinforces the view that going by fluid ounces is unreliable (so I wonder why David Schomer relies on it - unless he has changed to weight). Also, does it mean that the same beans will produce different densities of liquid at various points in their roasted life?


Anyone got an answer for this then ?


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## 4085 (Nov 23, 2012)

There is no answer, just opinion.....


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## Mrboots2u (May 10, 2013)

Phil104 said:


> It's not clear what Schomer includes in his 1.5 ozs - the photographs suggest that it includes the crema but he also makes the same point about visually checking (and of course time). I'd be interested to experiment with volume and see the difference.


Anyone got an opinion on this then


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## MWJB (Feb 28, 2012)

DavecUK said:


> The dissolved coffee solids doesn't add hardly any weight.


Typically, somewhere between 2.5g and 5g of what is in your shot is actually dissolved coffee.


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## DavecUK (Aug 6, 2013)

MWJB said:


> Typically, somewhere between 2.5g and 5g of what is in your shot is actually dissolved coffee.


mark, your welcome to pop round and we will weigh it accurately, because that's not what I have found.


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## MWJB (Feb 28, 2012)

Originally Posted by Phil104 View Post

"Also, does it mean that the same beans will produce different densities of liquid at various points in their roasted life?"



Mrboots2u said:


> Anyone got an answer for this then ?


For a given dose, yes, but only if you pull different length/weight/volume shots, or never change your grind setting. Usually, you would change grinder settings to get a reasonably consistent shot density & as the beans age.


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## MWJB (Feb 28, 2012)

DavecUK said:


> mark, your welcome to pop round and we will weigh it accurately, because that's not what I have found.


How much would you reckon the dissolved solids in a typical, palatable shot weigh?

It'll take a fair while to separate the dissolved solids from the shot, but I'm game if you are?


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## El carajillo (Mar 16, 2013)

Conversion from US fluid ounces 1.5 fluid ounces = 44.36 grams.


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## MWJB (Feb 28, 2012)

El carajillo said:


> Conversion from US fluid ounces 1.5 fluid ounces = 44.36 grams.
> 
> The density of a fluid will rise when a substance is dissolved in it. Compare density of sea water to fresh water. Whether the density difference in a small measure of coffee is measurable
> 
> I would have my doubts.


Use the same dose to make a french press at regular brew ratios (55-75g/l). Now use the same dose to pull a shot, can you detect a difference in concentration?


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## 7493 (May 29, 2014)

Is he talking fluid ounces or weight ounces I wonder?


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## Mrboots2u (May 10, 2013)

Rob666 said:


> Is he talking fluid ounces or weight ounces I wonder?


That would be super weird

Dose in g in

Weight in ounces ( weight out )


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## DavidBondy (Aug 17, 2010)

Mrboots2u said:


> That would be super weird
> 
> Dose in g in
> 
> Weight in ounces ( weight out )


Actually, it seems quite normal in the USA!

Speaking personally, I will go metric ounce by ounce!!!


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## AndyS (May 12, 2012)

Phil104 said:


> Thank you Mrboots. It reinforces the view that going by fluid ounces is unreliable (so I wonder why David Schomer relies on it - unless he has changed to weight).


Don't know if David has changed to weight, but at that time he was probably using ounces for the same reason that most people in the States are still using obsolete "Imperial" measurements -- if you've used a system for a long time, even an inferior system, it's hard to change. We stubborn Americans have yet to go Metric.



MWJB said:


> Typically, somewhere between 2.5g and 5g of what is in your shot is actually dissolved coffee.





DavecUK said:


> mark, your welcome to pop round and we will weigh it accurately, because that's not what I have found.


The amount of dissolved solids in espresso does not correlate very well with the liquid density. Espresso is a complex substance containing dissolved and suspended solids as well as dissolved and suspended gases.

Dissolved solids commonly comprise 5-12% of the brew.

Typical density of espresso is 1.02 times that of water.

Also, the density of water at 20C is about 4% greater than water at 95C.


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## 7493 (May 29, 2014)

Not so weird. I often mix units when it's convenient to do so. Until a very few years ago glass was sold in metric thickness but imperial area.


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## Mrboots2u (May 10, 2013)

Rob666 said:


> Not so weird. I often mix units when it's convenient to do so. Until a very few years ago glass was sold in metric thickness but imperial area.


Ah ok , just weird to me ... Child of the metric so know no different









Then again I refer to

journeys in miles

Height in feet and inches









Confused myself now


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## Charliej (Feb 25, 2012)

Over in continental Europe as well as here vehicle tyres are sold with metric measurement to describe the tyre width and sidewall height and the diameter in inches.

To answer one question 1.5 imperial ounces is 42.52 grams so not that far outside what some of us are pulling shots at from 16-20g do.

Martin I also imagine you don't drink beer by the ml or litre when ordering in the pub.


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## michaelg (Jul 25, 2013)

Now, what if you were using deuterated or tritiated water? Would volume be a better measure than weight? And if tritiated - does the radiation give it an added 'kick'?


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## majnu (Jan 31, 2014)

Chris from hasbean sent me this link when I wanted a 2oz shot glass to time my double espresso shot. I think using the formula is just a rough guide to aim for as with 17g ground coffee I aim to get 30g dose in 20 to 30 seconds.

http://colinharmon.wordpress.com/2010/10/24/falling-in-love-with-espresso-1-55-times-over-again/

I still want to buy a shot glass though lol


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## AndyS (May 12, 2012)

Rob666 said:


> Not so weird. I often mix units when it's convenient to do so.


Agreed, it's not weird, mixing units is common. Mixing units is fine for one's personal use, but when it comes to accurately communicating with others, or instructing others, it's confusing and constantly leads to errors.

Also, consistent units (grams to grams) are extremely useful in computing and transferring espresso brewing ratios.


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## AndyS (May 12, 2012)

michaelg said:


> Now, what if you were using deuterated or tritiated water? Would volume be a better measure than weight? And if tritiated - does the radiation give it an added 'kick'?


Don't know about the tritiated water, but since the EK grinder tends to produce a lighter-bodied espresso, I often compensate for it by substituting deuterated water for the regular kind. D2O is about 10% denser than standard H2O and it seems to give just about the right "heaviness" for the EK espresso.

YMMV.

And if you believe that, perhaps I can offer you a special discount price on Buckingham Palace?


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## sjenner (Nov 8, 2012)

El carajillo said:


> Conversion from US fluid ounces 1.5 fluid ounces = 44.36 grams.
> 
> The density of a fluid will rise when a substance is dissolved in it. Compare density of sea water to fresh water. Whether the density difference in a small measure of coffee is measurable
> 
> I would have my doubts.


The computer newspaper "The Register" has this conversion tool that might be useful... I have it on my favourites bar.

http://www.theregister.co.uk/Design/page/reg-standards-converter.html

They have a long running joke there about "Olympic Swimming pools" and other TV News measurements like "Double decker buses" etc. etc.

This might...

Or might not









Help.


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## Phil104 (Apr 15, 2014)

AndyS said:


> Don't know if David has changed to weight, but at that time he was probably using ounces for the same reason that most people in the States are still using obsolete "Imperial" measurements -- if you've used a system for a long time, even an inferior system, it's hard to change. We stubborn Americans have yet to go Metric.


 Does this mean that when Schomer describes ounces he means by weight (not volume) and so an ounce shot glass indicates weight?


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## Phil104 (Apr 15, 2014)

sjenner said:


> The computer newspaper "The Register" has this conversion tool that might be useful... I have it on my favourites bar.
> 
> http://www.theregister.co.uk/Design/page/reg-standards-converter.html
> 
> ...


Thank you for this Stephen. This seems to sum it up: 'As our technical wizard explains: "To turn a mile into anything else, it first needs to be converted into linguine".'


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## AndyS (May 12, 2012)

Phil104 said:


> Does this mean that when Schomer describes ounces he means by weight (not volume) and so an ounce shot glass indicates weight?


I believe he meant ounces by volume, but who knows?

Just another reason for folks to join the 21st century and express espresso output in grams....


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## Mrboots2u (May 10, 2013)

AndyS said:


> I believe he meant ounces by volume, but who knows?
> 
> Just another reason for folks to join the 21st century and express espresso output in grams....


Agree , as long as you don't make me order my " pints " by the litre in pubs though ......


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## DavecUK (Aug 6, 2013)

Phil104 said:


> Does this mean that when Schomer describes ounces he means by weight (not volume) and so an ounce shot glass indicates weight?


no a 1 oz shot glass is absolutely a measure of volume.


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## garydyke1 (Mar 9, 2011)

Mrboots2u said:


> Agree , as long as you don't make me order my " pints " by the litre in pubs though ......


''Can I have 568.3mls of xyz IPA please.''


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## AndyS (May 12, 2012)

garydyke1 said:


> ''Can I have 568.3mls of xyz IPA please.''


I always order my beer by mass: "May I have 520 grams of the IPA please?"


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## Mrboots2u (May 10, 2013)

AndyS said:


> I always order my beer by mass: "May I have 520 grams of the IPA please?"


I seem to find I denser the more mass of beer I drink ......


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## CoffeeDoc (Dec 26, 2012)

Surely the problems arise when you mix volume, mls, pints, drams with weight, stones, kilos, grams, you can use one or the other, any mix of units is fine provided you don't mix weight and volume, distance and area, don't worry about the units get the concept the same.


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## MWJB (Feb 28, 2012)

The trouble is that unless the "ounce" is explicitly identified, we don't know whether it's a fl. oz, a dry oz, a US fl.oz, a UK fl. oz. A line on a glass is just a stripe of paint, it's a nominal marking, then we also have parallax error. If you are trying to extract coffee to to +/-1% of the dose (not that you have to, if you don't want to) all of these little differences quickly eat up your margins...it's like throwing half house bricks at a dart board, "did I hit the treble 20?"


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## Charliej (Feb 25, 2012)

I love your analogy Mark, as they say close only counts with horseshoes and hand grenades.


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## MWJB (Feb 28, 2012)

Easy, tap water, no crema...shot glasses were sold as "1oz to line".

A bag of coffee for the person who gets all 3 weights right...to +/- 0.1g..

EDIT seems a bit tight 0.1g, so amended to +/-1% of weight, rounded to nearest 0.1g.


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## Mrboots2u (May 10, 2013)

36-32-36.....

Miss Ireland 1983


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## MWJB (Feb 28, 2012)

Errrm, forgot to say..."I have e-mailed the weights to Mr Boots to act as adjudicator..."


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## Mrboots2u (May 10, 2013)

MWJB said:


> Errrm, forgot to say..."I have e-mailed the weights to Mr Boots to act as adjudicator..."


You mean my entry isn't a serious one ......


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## MWJB (Feb 28, 2012)

"Don't tell 'em your name Pike!"


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## hotmetal (Oct 31, 2013)

I wonder whether the 2273ml of Sam Smiths I just drank (excessive head or 'crema' notwithstanding), weighs more than the equivalent volume of fizzy Lager? On second thoughts, DILLIGAF!

Do bits of crisps count towards TDS?

BTW, after this morning's coffee catastrophe, I have realised that the very least of my worries is the putative 1% variance between grams and ml of any given shot. 3 chokers, all the same grind as yesterday's, different doses +/- 1g. I didn't think I tamped that hard. ..


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## majnu (Jan 31, 2014)

Half Life 3 will be confirmed based on this thread


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## Phil104 (Apr 15, 2014)

MWJB said:


> Errrm, forgot to say..."I have e-mailed the weights to Mr Boots to act as adjudicator..."


 I've probably misunderstood the complexity of this quiz. Assuming conservation of volume, if it's 1 fluid oz in each glass then they should all contain the same, and as it looks like water (not gin, vodka or another clear but potentially denser than water liquid), then the answer should be 29.57 gms (if US fluid ounces) or 28.41 gms if imperial fluid ozs. The convertor that Stephen posted earlier doesn't make it easy to work out fluid ozs but if I assumed that there is 1 cubic inch in the glasses then in Vulture Central Units it is 0.0313 grapefruit or 0.0285 Bulgarian airbags (C-Cup Posh Spice). I have also emailed the quiz to David Schomer and offered to split the prize with him but for the time being am sticking by my answers.


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## The Systemic Kid (Nov 23, 2012)

I've got David Schomer's book - will check it out.


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## The Systemic Kid (Nov 23, 2012)

Phil104 said:


> So, simply out of academic interest, when Schomer says 1.5 ounces what does he mean in grams?


In his book, Schomer refers to *volume output* rather than weight output citing the example - 'volume for a double ristretto being 1.1.5oz using 16grms dose'.

Volume equates to fluid ounces as opposed to weight - so it should read fluid ounces. In the chapter on espresso theory, Schomer lists the defining variables - water temp, time ect and *volume of shot. *. Pretty unambiguous


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## MWJB (Feb 28, 2012)

Phil104 said:


> I've probably misunderstood the complexity of this quiz. Assuming conservation of volume, if it's 1 fluid oz in each glass then they should all contain the same, and as it looks like water (not gin, vodka or another clear but potentially denser than water liquid), then the answer should be 29.57 gms (if US fluid ounces) or 28.41 gms if imperial fluid ozs. The convertor that Stephen posted earlier doesn't make it easy to work out fluid ozs but if I assumed that there is 1 cubic inch in the glasses then in Vulture Central Units it is 0.0313 grapefruit or 0.0285 Bulgarian airbags (C-Cup Posh Spice). I have also emailed the quiz to David Schomer and offered to split the prize with him but for the time being am sticking by my answers.


It's tap water, density is 1ml to 1g (or certainly close enough for this purpose).

The glasses are not marked as to whether they are US or UK.

The miniscus is level with the marked 1oz lines (Should it be? Should it be above the lines? At the base of the lines?)

There are 3 glasses, so I'm looking for 3 weights...even if 2, or even 3, are the same. I offered a bag (250g, UK roaster) of coffee instead of an elephant, or £1,000,000 (though, I was tempted to) because statistically there is a chance that someone will get it right...and I don't have an elephant or £1,000,000...and I wouldn't give either away if I did.


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## MWJB (Feb 28, 2012)

So Phil104 you have gone with:

Guess #1: 29.57 +/-1% (29.3-29.9)

Guess #2: 28.41 +/-1% (28.1-28.7)

What's guess #3? C'mon, c'mon, the coffee is degassing...;-)


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## Phil104 (Apr 15, 2014)

MWJB said:


> It's tap water, density is 1ml to 1g (or certainly close enough for this purpose).
> 
> The glasses are not marked as to whether they are US or UK.
> 
> ...


Okay. I'm more certain than ever that I won't get it right and in any event I would pass on the elephant and the £1,000,000 (it wouldn't make me happy).... a giraffe on the other hand (or linguine):

So my answer:

Glass number 1: 29.57; number 2: 29.57; number 3: 29.57 (all US fluid ounces)

Glass number 1: 28.41; number 2: 28.41; number 3: 28.41 (all imperial fluid ounces)

I appreciate that there are other variables that I can't account for - I was mainly thinking of height above or below sea level and air pressure. If there is wide variation between the weights then it does beg the question of how accurate the marks are on those glasses. (I have still not heard from David S.)


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## MWJB (Feb 28, 2012)

2 goes Phil? Greedy...

Good point, I live between 11m & 40m above sea level...

Anyone else? You can have 2 goes too...


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## Phil104 (Apr 15, 2014)

MWJB said:


> 2 goes Phil? Greedy...
> 
> Good point, I live between 11m & 40m above sea level...
> 
> Anyone else? You can have 2 goes too...


 Sorry - wasn't intending to be greedy but if you really want me to opt for US or imperial, I will. It's too late now, to adjust any of my answers to take account of seal level but some else (doubtless the many others even now working out the answers) can make good use of that information.







:act-up:


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## MWJB (Feb 28, 2012)

Well Phil it looks like you are the only entrant in the "convert 1fl.oz to g" competition. Time for the big reveal...drumroll please....









OK, I'll take tumbleweed...









Sadly, you were way out...not in your logic, but in the quite reasonable assumption that logic would actually help! The glasses are made to a wide tolerance & marked by a machine that has no interest in oz/mls & their relationship to grams, nor that of ml to oz (of any kind).

The 3 glasses held 31.6g, 35g & 38g (3g difference between 2 seemingly identical glasses) respectively, when filled to the "1oz" line. 9% difference between each and 18% from lowest to highest. How can you use volume if you don't know what the volume is, that you are looking at? Of course, you could determine the volume (within a range) by weighing & marking each glass (ignoring the crema/no crema debate)...why not cut out the middle man & just weigh?


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## Phil104 (Apr 15, 2014)

MWJB said:


> Well Phil it looks like you are the only entrant in the "convert 1fl.oz to g" competition. Time for the big reveal...drumroll please....
> 
> 
> 
> ...


Thanks for organising the competition Mark - clearly captured the imagination of forum members (!). Is it the competition with the lowest number of entrants ever? Anyway, after this reveal, I am only now recovered enough for the enormity of it to begin to sink in and with it the ability to type a response. Okay, I'm devastated to have been way off the mark (literally as it happens). In the process of this, though, what I hadn't appreciated (presumably most people using a lined shot glass already accept it) is their inaccuracy. Given that some of them are marketed as an aid to calibration, the obvious step to take is to calibrate any glass before use, which is what you describe. Implicitly, it further complicates my original question in that one then needs to know the make of glass that David Schomer is using and the volume (let alone weight) he is actually achieving (although I know he emphasises all the other factors).

Maybe this should be a separate question. In his book he is consistent about time (25-30 seconds) and volume (1.5 ozs for a double ristretto) but the 16 gms of ground coffee (on pages 113 and 116) becomes 17 (actually, 'about 17 grams') on page 153 in his 'one sheet method' to cut and laminate etc. Does anyone know why there is this discrepancy?


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