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Conversion errors

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Janet Yang's picture
Janet Yang

Conversion errors

I was looking up the number of grams in ¾ cup of sugar, and found a table with some errors. It's at 

http://www.pastryscoop.com/category/look-it-up/sugar/

It says

1/3 cup = 4 1/2 ounces = 150 grams;  3/4 cup = 5 1/4 ounces = 170 grams;  2 cups = 1 pound = 500 grams 
but should be
2/3 cup = 4 1/2 ounces = 133 grams;  3/4 cup = 5 1/4 ounces = 150 grams;  2 cups = 17 1/4 ounces = 400 grams 
Their email address doesn't work anymore, so I couldn't send them the corrections. Janet
suave's picture
suave

Frankly, you did not do much better, since according to you 400 g equals 17¼ oz.

MANNA's picture
MANNA

WOW! That's pretty much rude and just as unhelpful.

suave's picture
suave

Exactly which part of pointing out an error in basic math is rude?

MANNA's picture
MANNA

The statement came across rude to me upon reading it. Its not what you say its how you say it.I struggle with such things myself.

suave's picture
suave

Well, perhaps, but how do you sugarcoat it when someone rams through what is probably the most important metric/imperial conversion, that is 1lb = 16oz = 454g?  More importantly, why would you want to?

adri's picture
adri

Don't worry. I for example didn't find it rude at all.

suave's picture
suave

That's certainly nice to hear :)

Janet Yang's picture
Janet Yang

The actual figures are closer to 14.17 ounces and 401.73 grams. 

If you're measuring water, butter, etc., the figures will be different. For example, for 2 cups of water it's 16.69 ounces and 473.18 grams.

Bob Marley's picture
Bob Marley

Janet, 2C of water occupies 16 ounces volume and weights 16 ounces here in America.  The CUP MEASUREMENT can vary by country.

adri's picture
adri

Hm, 4.5 ounces is 133g and not 128g?

17.25 ounces are 489g and therefore colser to 500g than to 400g.

Wolframalpha gives me 134g for 2/3 US-cups and 129g for 2/3 Canadian cups.

... well?

Janet Yang's picture
Janet Yang

I think they simply doubled the amounts used for 1/3 cup, and those numbers were already rounded.

adri's picture
adri

Then why did you do this rounding?

I just took your number. How did you convert oz("international avoirdupois ounce") to kg? This should be a simple factor of 0.0283495... .

 

Janet Yang's picture
Janet Yang

You're right about the rounding…I should not have allowed the doubling, as it multiplies the error.

The conversion factor varies according to the density of the substance. The conversion factor for granualated sugar is 0.02510792670681. The conversion factor for pure water is 0.02957352969, which is different from the one you are using, but I don't know why.

 

adri's picture
adri

No!

One oz ("international avoirdupois ounce") feathers has the same conversion factor to kg as one oz of lead!

Both are units of mass.

eod

MANNA's picture
MANNA

Janet,

I use this page from King Arthur Flours website.

http://www.kingarthurflour.com/recipe/master-weight-chart.html?utm_source=sli&utm_medium=redirect

It shows White sugar as 1-cup = 7-oz.

I use 28.35g in an ounce.

So, 1-Cup = 198.4g

Multiply by .75 and you get 148.8g in 3/4-cup of sugar.

Hope this helps.

Janet Yang's picture
Janet Yang

Thanks, I used 150 grams, which is much closer to your figure than 170 grams!

Bob Marley's picture
Bob Marley

@Janet Yang:

It would be best for you to find recipies that list the ingredients using both weight and volume.  Weight, however, is a more accurate measure for ingredients as volume can change with changes in temperature.  Just ask any chemist.

Best  8)

MisterTT's picture
MisterTT

reason to weigh ingredients, changes in volume are of course existent, but negligible. The real reason is that flour density varies due to the fineness of the grind, scooping method into the measuring cup and so on. Just compare how much does a cup of sifted cake flour weigh and bread flour straight from the bag.

Janet Yang's picture
Janet Yang

Because then my table must be based on some accepted standard for room temp. 

Bob Marley's picture
Bob Marley

YES, Janet Yang.  It's called STP, standart temperature and pressure in the chemistry field.

This whole thread can be avoided if you adopt metric weights as your standard of measurement.  Avoid volume measurements as volume and therefore density varies with temperature.  Screw the British standard of measurement which is termed avdp, avoirdupoids, meaning to have weight.  The AVDP relies on sixteenths, real confusing cr*p imho and I possess almost four years of college chemistry coursework.

In other words get youself a digital scale.  I use the MyWeigh KD8000 and it's exact and correct in terms of weight measurement right down to the gram.

Janet Yang's picture
Janet Yang

However, I was using a recipe from the 8th Pillsbury Bake-Off, which called for 3/4 cup of sugar. Of course it would have been easy to use measuring cups, but I wanted to know the exact measure in grams, just for the record. That's how I came across the "3/4 cup = 170 grams of sugar" on that old website.

Bob Marley's picture
Bob Marley

The density of flour, MisterTT, can vary due to humidity and flour type and whether one fluffs it prior to scooping.  And how long it's sat in the bag. 

sandydog's picture
sandydog

Officially, I am led to believe, a US Cup is 240ml (or 8.45 imperial fluid ounces.) This is slightly different from an Australian, Canadian and South African Cup which is 250ml. In the UK I think it is 284ml.

I guess that as long as you use the same cup for measuring out each of your ingredients, the proportions should work out the same using another country's recipes/cups.

I prefer to weigh things in grammes as I think they are the same worldwide - Am I correct?.

Brian

Janet Yang's picture
Janet Yang

which is just one good reason for going metric.

Bob Marley's picture
Bob Marley

Brian, YOU are correct.  Grams are the same worldwide whereas volume measurements in terms of cups are not.  Weight supersedes all.

MANNA's picture
MANNA

Overall I'm amazed at how much input everyone has on this. Not to mention the extent of knowledge on a subject such as units of measure. Really makes me happy to be a part of this community.

Janet Yang's picture
Janet Yang

That's how I memorized it in Home Ec. It's an easy alliteration to remember, but evidently not quite accurate. "A pint's a pound" means a gallon is 8 pounds, but my resident (former) engineer insists that a gallon is 8.34 pounds.

This reminds me of a book on making chain-mail jewelry. I was having trouble getting the patterns to work, and finally discovered that the wire gauges were wrong. I wrote to the author and It turned out the book used British wire gauges instead of the U.S. wire gauges she had specified. 

I do wish we would convert to the metric system!

Bob Marley's picture
Bob Marley

For the first 10 years that I baked bread I struggled when it came to rescaling recipies using those darned cup measurements; rescaling by weight and percentages is much much faster .  And since I got my digital scale, I never looked back at using my cups; and, I'll reiterate, weighing stuff takes much less time than using volume measurements.

PetraR's picture
PetraR

I always weight out Ingredients , in Germany we do not have Meassuring Cups and / or Spoons.

To weigh out Ingredients is the most accurate way of doing it.

The metric systeme is what I grew up with and the easiest to work with.

The only time I do use cups * normal cups no meassuring cups *is when I make rice.

1 Cup of rice for 2 Cups of water.

I was told by one Lady that she would NEVER use scales as it is to complicated , and that was the Lady that often complained that her cakes and baked good always varied from dense to light even though she used the same recipe.

Bob Marley's picture
Bob Marley

Probably all of your German-written cookbooks specify measurements by weight - something that should have been initiated in the U.S. decades ago.

adri's picture
adri

Pues, no. Most is specified by weight. But then there still are the "teaspoons". And as there is no official volume for teaspoon, percentages really can get off. Some recipes use "heaped teaspoons" some not.

PetraR's picture
PetraR

Yes Bob Marley, almost all are done in weight, but as adri said, there are teaspoons for example.

Using a teaspoon is not to bad though, we do have teaspoons and spoons and tablepsoons.

When it comes to heaped teaspoons it is just what it is and one can not get to wrong with it.

Here in the UK people mostly use the metric systeme now , but , like my Mother in Law, she still uses ounces and fluid ounces..

 

adri's picture
adri

I have very different types of teaspoons.

I just picked 2 randomly: One gave me 81g for 10 heaped ones. The other one gave me 96g.

This is 18.5% more.

 

Measuring in weight, I actually don't care, if the recipe is in gram, stone, ounces or bakers-%. As long as it is always the same unit. I always just use the proportions. Only sometimes, when I make something in pans that have to be filled exactly, I need an anchor point.

Adrian

PetraR's picture
PetraR

1 Tsp and 1 Tbsp for Sugar would be.

1 tsp = 5g

1 Tbsp = 15g

 

But there are so many things that tsp and tbsp are used for and than those numbers do change A LOT.

http://www.chefkoch.de/magazin/artikel/500,2/Chefkoch/Loeffelmass-in-Gramm.html

I am sorry , this is a German chart.

EL = tbsp

TL = tsp

None of those numbers are for heaped spoons.

The first number is always for the tsp and the second number for the tbsp

At the bottom are some more meassurments with tbsp and tsp.

So I just do what the recipe says and use 1 tsp of this or that or one tbsp of this or that.

If they want to be precise in the recipe they need to give us grams so that we can weigh. sighhhhh

I always use a normla tsp and a normal Tbsp, not had any problems with it , yet.

 

Janet Yang's picture
Janet Yang

Did you know that the proportion of rice to water varies? The longer the time since harvest, the drier the rice gets and the more water it absorbs. I have never found the difference worth dealing with, though.

Janet Yang's picture
Janet Yang

Did you know that the proportion of rice to water varies? The longer the time since harvest, the drier the rice gets and the more water it absorbs. I have never found the difference worth dealing with, though.

PetraR's picture
PetraR

Oh , I was not aware of this, I must say, the method one cup rice to 2 cups of Water have always worked for me, I never saw a difference.

CatPoet's picture
CatPoet

A european teaspoon messurment ( not a real one) is  5 ml  and an American is about 4.9 mL

Mini Oven's picture
Mini Oven

moisture and need less water during a rainy season.  One of the reasons kernels of rice are added to salt shakers is to prevent the salt from clumping when the salt attracts moisture.  

I tend to use less than 2 cups of water for 1 cup of white rice because I wash the rice first.  :)

PetraR's picture
PetraR

My husband does the rice washing, I just do the 1:2 ratio and so far it worked fine, maybe I am just lucky.

I also never do what it says on the Label, I cook all rice the same.

I put the Water in , salt, brint it to the boil, put the rice in, bring back to a boil , turn the heat on very low, lid on and 10-12 minutes. Rice is done.

No matter what rice my husband cooks, he always produces Sticky rice. lol

adri's picture
adri

Actually they just help loosening the salt when shaking. You could also use small stones ;)

Mini Oven's picture
Mini Oven

and whoa to the person who grabs the salt shaker, unscrews it and dumps salt & rocks into the goulash!  Shaking action is the second function of the rice.   

I've seen plenty of rocks in some salt packages over the years and it didn't help with the moisture.  Some countries even have lids on the salt shakers.  Others serve a salty sauce instead for dipping:  soy, various fish sauces, etc..  Or serve salt in a tiny dish for "pinching."  

 

PetraR's picture
PetraR

I also was always told that rice helps to draw the moisture out of Salt.

 

Janet Yang's picture
Janet Yang

Ever dropped your cellular phone in—well, has it ever gotten wet? Supposedly you can dry out the phone by burying it in a bag of rice. 

adri's picture
adri

But no one ever removed soaked rice from the salt. If it would help it therefore would just help on a very short term.

Adrian

Bob Marley's picture
Bob Marley

A simple sieve could filter the rice out and away from the salt.

Janet Yang's picture
Janet Yang

I don't know the reason for putting rice in salt shakers. It could be there as a desiccant, but I always assumed it was to keep the holes from clogging by breaking up clumps. (That's because I use rice as a mild abrasive, to clean out bud vases.) 

adri's picture
adri

That's totally what I believe.

I had to look up, what bud vases are. (I thought bud was an US beer ;)) I think I'll try this next time.

Adrian

David Esq.'s picture
David Esq.

People also recommend to put wet electronics in a bag full of dry rice to help draw out the moisture. Whether it works is another matter....