Author Topic: Conversion from weight to volume  (Read 8265 times)

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Offline Steve

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Conversion from weight to volume
« on: September 30, 2003, 06:03:18 PM »
Since commercial (professional) recipes are always expressed in units of weight, I thought it'd be handy to actually weigh various ingredients and determine their equivalent volume.

I used my digital kitchen scale (accurate to 0.05 ounce) and proceeded to weigh one (1) cup of some common pizza ingredients.

1 cup sifted flour = 4.65 oz.
1 cup fluffed/scooped flour = 5.30 oz.
1 cup yellow cornmeal = 4.50 oz.
1 cup water = 8.33 oz. (avoirdupois)
1 cup olive oil = 7.90 oz. (avoirdupois)
1 cup salt = 9.45 oz.
1 cup sugar = 6.75 oz.
1 cup butter (or shortening) = 8.00 oz.
1 cup active dry yeast = 6.40 oz.
1 cup dried oregano flakes = 1.15 oz. (34 grams)
1 cup dried basil flakes = 1.05 oz. (30 grams)
1 cup granulated garlic = 5.45 oz. (156 grams)
1 cup ground black pepper = 3.45 oz. (98 grams)

Here, all ounces are expressed as weight (avoirdupois) as opposed to fluid ounces. Thus, 8 fluid ounces of water weighs 8.33 ounces avoirdupois. Conversion to teaspoons and tablespoons should be pretty straightforward.  ;D

1 cup = 48 teaspoons
1 cup = 16 tablespoons
1 tablespoon = 3 teaspoons
1 fluid ounce = 2 tablespoons (6 teaspoons)
8 fluid ounces = 1 cup
« Last Edit: January 29, 2005, 12:10:38 PM by Steve »
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Offline Steve

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Re:Conversion from weight to volume
« Reply #1 on: September 30, 2003, 06:35:08 PM »
I almost forgot to mention the formula to perform the conversion:

Since we know the weight of one cup of each ingredient, conversion is simple:

If the recipe calls for 0.25 ounces of salt, here's the math:

1 cup salt weighs 9.45 ounces.

Take 0.25 / 9.45 = 0.026455026455026455026455026455026  ;)

Ok, that means 0.25 ounces of salt is equivalent to 0.026 cups. To convert this into teaspoons, we simply multiply by 48 (there are 48 teaspoons in a cup):

0.026 x 48 = 1.248 teaspoons or, rounded up, 1 1/4 teaspoon.

For 0.25 ounces of sugar, it's 0.25 / 6.75 = 0.037 cups. 0.037 x 48 = 1.78 teaspoons, or roughly 1 3/4 teaspoons.  8)
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Offline Steve

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Re:Conversion from weight to volume
« Reply #2 on: October 01, 2003, 09:46:28 AM »
Found a website which lists the number of grams per cup for some common baking ingredients (see: http://www.gourmetsleuth.com/gram_calc.htm)

I converted grams to ounces and got the following numbers:

1 cup olive oil = 7.587 ounces
1 cup butter = 7.973 ounces
1 cup flour = 4.391 ounces
1 cup salt = 10.256 ounces
1 cup shortening = 7.201 ounces
1 cup sugar = 7.025 ounces
1 cup water = 8.325 ounces
1 cup active dry yeast = 7.868 ounces

Hmmmmm.... I think I'm going to stick with my original numbers since I measured them myself.
« Last Edit: October 01, 2003, 09:47:33 AM by Steve »
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Offline Randy

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Re:Conversion from weight to volume
« Reply #3 on: October 01, 2003, 12:31:05 PM »
Good information Steve.
Many of the textbook cooks now concede a typical cup of flour is 5 oz.  That's the figure I use when I get a recipe based on cups, not weight.

Randy

Offline Pierre

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Re:Conversion from weight to volume
« Reply #4 on: January 24, 2004, 07:17:12 PM »
here's a website with a very good conversion programm for converting over 400 hundred Units of measurement in some 24 different categories.

The Pro version can be executed 100 times. Here is the link:

http://www.esbconsult.com/esbcalc/esbunitconvpro.html

The Freeware version has has a few lesser units of conversion but is otherwise not limited.

http://www.esbconsult.com/esbcalc/esbunitconv.html


Offline Steve

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Re:Conversion from weight to volume
« Reply #5 on: September 21, 2004, 06:38:08 PM »
I was just going back over my notes from last year (above) and I decided to try to nail down the EXACT "official" weight/volume of all-purpose flour.

As you see from my notes above:

1 cup sifted flour = 4.65 oz. (avoirdupois)
1 cup "fluffed/scooped" flour = 5.30 oz.

According to nutrition facts label on the many different bags of flour under my counter, 1/4 cup of flour = 30 grams, which would put a cup of flour at:

1 cup flour = 120 grams = 4.23 oz.

Hmmm... and a quick Google yields:

1 cup flour = 112 grams = 3.95 oz.

Something just doesn't quite add up here. So, I contacted the National Institute of Standards and Technology (Weights and Measures Division) and received the following information:

1 cup all-purpose flour = 113 grams = 3.99 ounces avoirdupois.

So, for all practical purposes, and according to the NIST, one cup of all-purpose flour should weigh approximately 4 ounces.

Whew!!  ::)

Now that that's settled, I will make a note of that somewhere on the website and change all of the recipes to reflect this new information.  8)
« Last Edit: September 21, 2004, 06:43:08 PM by Steve »
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Offline Randy

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Re:Conversion from weight to volume
« Reply #6 on: September 21, 2004, 07:04:59 PM »
I hate say this but each mill sets their cup weight.  As an example the softer WhiteLily flour 4.25 oz per cup and KA uses 4.5 oz.  That is one reason why they have baker's percent to avoid the whole issue.  Add to that the typical home measurement is 5 oz per cup.

I still like your research. 8)

Randy

Offline Steve

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Re:Conversion from weight to volume
« Reply #7 on: September 21, 2004, 07:14:23 PM »
I understand completely, Randy. But, I want to come up with "the official" volumetric weight of flour... even though it will vary according to each mill, moisture content, etc...

So, if the National Institute of Standards and Technology (http://www.nist.gov) says that a cup of all-purpose flour weighs 4 ounces, then that's the number that I want to use on the website!  ;) 8)
« Last Edit: September 21, 2004, 07:15:12 PM by Steve »
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Offline Steve

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Re:Conversion from weight to volume
« Reply #8 on: September 21, 2004, 07:23:51 PM »
Dang!!  >:(

I just went back and re-read the literature from the NIST and apparently I glossed over the "Approximate Weights of some Commodities" heading.

APPROXIMATE!?!?!  :P

Ok, Randy, you win!

What does everyone here think that I should use for the recipes on the site?

I'm leaning towards 4.5 ounces at this point.  :-\
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Offline Randy

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Re:Conversion from weight to volume
« Reply #9 on: September 22, 2004, 08:31:01 AM »
I think Pierre started a thread some time ago asking people to weigh a measured cuo of flour and I think it was around 5 oz per cup.  Shirley O. Corriher said she gave up on perfect measured cup of flour and now uses a scooped cup weight of 5.6 oz per cup.  
I think it is to your credit for accuracy that you addressing this issue up front instead of sloughing it off as humidity being the reason why recipes are problematic in the wetness of the dough.
Maybe the middle of the road and say 5 oz per cup might do.
.


Online Pete-zza

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Re:Conversion from weight to volume
« Reply #10 on: September 22, 2004, 06:22:42 PM »
This is one of those topics that can drive you to drink :P.

Over the weekend, I decided to try to weigh a cup of tap water.  I poured the water into a glass measuring cup and waited for the water to settle before weighing it.  I then repeated the exercise a few more times.  Each time I weighed the "cup" of water, I got a different measurement.  I concluded that I couldn't eyeball the level of the water in the cup well enough to get an accurate and unwavering weight measurement.

Flour can be even worse, not only because the flour can be loosely packed, sifted or tightly packed, but also because different kinds of flours have different weights and there may also be differences among different brands of the same kind of flour.  This means having to have volume equivalents for all the different kinds and brands of flours.   Likewise for the many types and gradations of cornmeal.  Ingredients like salt, sugar  and yeast tend to be less problematic.  Most people don't have scales, or they are not accurate enough to measure the ingredients that are used in relatively small quantities, such as salt, sugar and yeast, so most recipes tend to specify those ingredients by volume anyway.   So, the problem seems to be most severe with flour.  

It may not be all that important to be accurate in specifying flour by volume, since there is no unanimity on the subject and trying to select from among diverse opinions will leave you unsatisfied at one point or another.  It's like trying to solve a riddle wrapped up in a mystery inside an enigma.  It may be more useful to point out to users that it may be necessary to make adjustments to flour and water, or both, in the course of practicing a pizza dough recipe.  Increasingly, in my dough recipes, especially those specifying flour and water by volume, I have taken to putting a "disclaimer", so to speak, to alert the user that adjustments in flour and/or water may be necessary.  This is where it is important, as has been pointed out many times before at this forum, to be as careful and detailed as you can in explaining the ingredients, procedures, temperatures, etc., and what the product should look and feel like at different stages.  I know people who have learned enough about these matters so as to be able to make pizza doughs without weighing anything.  They throw a few handfuls of flour into a machine, add salt, yeast, etc., by eyeballing things, and then add just enough water to bring everything together--tweaking flour and/or water here and there as necessary--until the dough is smooth and elastic and passes the windowpane test.  

I have recently started to adopt the practice of converting flour weights to volumes in my favorite recipes.  This is for the benefit of others who either do not have scales or are too lazy to use them.  After weighing the flour in a recipe, I scoop it into a measuring cup by the tablespoonful and then try to determine what the volume is by eyeballing the markings on the cup.  As long as I am consistent in doing this and advise the user to scoop flour into a cup in the same way, I should come reasonably close.  I am going to rely on my "disclaimer" anyway, so it isn't all that critical.  

If there are not that many recipes that need volume conversions, I would be inclined to select one weight for a cup of each of the three major flours used in making most pizza doughs--one for all-purpose flour, one for bread flour and one for high-gluten flour.   And one for a generic cornmeal.  As long as those weight measurements are used consistently, and they are arrived at using consistent procedures (such as tablespoon scooping into a measuring cup and weighing), users shouldn't become confused.  

Peter

« Last Edit: September 22, 2004, 06:31:06 PM by Pete-zza »

Offline Steve

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Re:Conversion from weight to volume
« Reply #11 on: September 22, 2004, 08:43:31 PM »
Oh, you can bet that there will be a disclaimer:

DISCLAIMER: Buy a scale!


 ;)
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Online Pete-zza

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Re:Conversion from weight to volume
« Reply #12 on: September 22, 2004, 09:20:32 PM »
One of the first items I got for my daughter-in-law when I was buying all of the pizza paraphenalia for her to use was a scale.  It was a simple and inexpensive one, but it worked and she used it.  When I got a nice digital model, a Soehnle Futura, I liked it so much that I got one for her too.  I can't wait to see your posted recipes with the disclaimer "Caution to users: Buy a scale"  ;D ;D.  I do admire your lofty goals however ;D.

Peter

Offline DKM

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Re:Conversion from weight to volume
« Reply #13 on: September 23, 2004, 01:38:13 PM »
Don't forget that a volume of water a different tempatures can weigh different.  Not so much a worry when dealing with a cup or so, be use to weigh water by the pound.

DKM
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Offline Lars

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Re:Conversion from weight to volume
« Reply #14 on: October 10, 2004, 06:11:54 PM »
I've been very frustrated trying to get the right proportion of water to flour, and so I'm thinking I will switch to using my scale.  However, it is accurate only to 0.2 oz, and I don't know if that is accurate enough for the water, although I'm sure it is for the flour.  I have a spring scale in addition to the postal scale, but I think it is less accurate.  I always seem to end up adjusting the recipe as I make it anyway, but once I had to make an adjustment of 2 cups of flour, and I knew that was too much.

Offline Steve

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Re: Conversion from weight to volume
« Reply #15 on: January 29, 2005, 12:12:18 PM »
I updated the original message at the start of this thread to include weights of 1 cup of the following ingredients: Oregano flakes, basil flakes, granulated garlic, and ground black pepper.
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