# Measuring potatoes



## Maureen Urlaub (Aug 21, 2008)

When a recipe calls for l.5# cubed potatoes, how many cups are needed?


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## sattie (Aug 21, 2008)

Do you have a digital scale?  That would be the best way, but not sure how many cups that would be.  Maybe 3?


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## babetoo (Aug 22, 2008)

welcome to dc maureen

babe


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## suziquzie (Aug 22, 2008)

you would have to weigh them... they are going to fit into your measuring cup differently depending on the size of your cubes.... 
weighing is the only way you're going to get it precise.


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## Adillo303 (Aug 22, 2008)

1 5# of potatoes sounds like a 5 pound bag of potatoes that you buy at the store. Just use the whole bag. They weighed it for you.

AC

BTW - Welcome to DC


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## BreezyCooking (Aug 22, 2008)

Adillo - I think the OP meant 1-1/2 (aka 1.5) pounds of cubed potatoes - not one 5# bag of potatoes.

Anyway, what I do for a recipe like this - since I don't have a digital scale - is to buy a bag of potatoes containing taters of pretty much the same size.  I then count the potatoes & divide by the weight of the whole bag.  It's then easy to basically figure out how many potatoes make the weight I need for the recipe.

And really - how many potato recipes are there where you need a spot-on direct hit re: weight?


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## pacanis (Aug 22, 2008)

BreezyCooking said:


> Adillo - I think the OP meant 1-1/2 (aka 1.5) pounds of cubed potatoes - not one 5# bag of potatoes.
> 
> Anyway, what I do for a recipe like this - since I don't have a digital scale - is to buy a bag of potatoes containing taters of pretty much the same size. *I then count the potatoes & divide by the weight of the whole bag. It's then easy to basically figure out how many potatoes make the weight I need for the recipe.*
> 
> And really - how many potato recipes are there where you need a spot-on direct hit re: weight?


 
What if the recipe calls for peeled potatoes?


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## BreezyCooking (Aug 22, 2008)

Absolutely no difference as far as I'm concerned.  Like I said, unless there's some reason why the particular recipe definitely absolutely requires a spot-on exact measurement, I do it just as I said.  You know, it's all too easy to get way too anal about recipes.


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## Chief Longwind Of The North (Aug 22, 2008)

Find the specific density per unit volume of the particular potato cultivar you are planning to use. Then dig out your calculus book and find the formula and technique for determining the volume of a potato. Once the volume is found, then simply divide the volume by the density to derive the weight, as in W=mass/volume. Then select sufficient potatoes to fill the correct voume, before cubing of course.

Or, as was stated above, weigh a couple of spuds, peel them, and dice them up.

Seeeeeeya; Goodweed of the North

(Oh, and that smilee that's being conked on the head, that's not you, but me for being so silly.)


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## pacanis (Aug 22, 2008)

You were being silly, GW?
For the heck of it I googled: 1.5 lbs of potatoes = ? cups, and you know what I got?
A page saying there wasn't an answer to that question. 

I thought maybe you were onto something


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## Chief Longwind Of The North (Aug 22, 2008)

pacanis said:


> You were being silly, GW?
> For the heck of it I googled: 1.5 lbs of potatoes = ? cups, and you know what I got?
> A page saying there wasn't an answer to that question.
> 
> I thought maybe you were onto something


 
Indeed, there is a way to measure the volume of a potato using calculus.  We had to determine the volume of several odd shapes that had no geometric straight lines, or perfect curves.  In fact, calculus is often described as the first real math because it allows you to determine close to exact values from imperfect shapes.  Once the volume of something is found, then it is just a matter of determining the specific weight of a substance and then plugging the values into into an algebraic formula.  But it seems to me that this is a very tedious process for finding the folume of a certain weight of potatoes.  It's much easier to weigh a large, say, 8 cup measuring cup, and then adding sifficient skined, cubed potato to achieve the same thing.  The masuring cup gives you the volume, and the scale gives you the weight.

I haven't had to use any calculous techniques for many years and so would stand very little chance at determining anythiing but the most basic integrals and derivitives at this point.  But it can be done.

Seeeeeeya; Goodweed of the North


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## GotGarlic (Aug 22, 2008)

sattie said:


> Do you have a digital scale?  That would be the best way, but not sure how many cups that would be.  Maybe 3?



A digital scale is not necessary - an analog one works just as well and costs 1/4 as much.


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## Chief Longwind Of The North (Aug 22, 2008)

Ok. The easiest say to do this is with an 8 cup measuring cup and a scale that will handle the weight of the cup plus 4 cups of water. Fill the measuring cup with 4 cups of water and weigh it. Then add one potato. Using the measuring cup, determine the potato volume by measring the volume of water with the potato, and subtracting the original 4 cups from it. That will give you the potato volume. Next, measure the weight of the combined water and potato, again subtracting the original weight from the new weight. That will give you the weight of the potato. Now, divide the weight of the potato by the volume and it will give you the weight per volume of the potato. Using that ratio, figure out the volume per 1.5 lbs of potato.

I found online that a potato weighs 1.6 gram per mililiter, or 1600 grams per liter. I also found conversion charts that gave me the following:
1 lb. = 453.59 grams
1 liter = 4.226 cups. Using a bit of alegebra (no calculous required), I found that 1.5 lbs. of potatoes = 1.8 cups, or one and four-fifths cups.

There. It's done. Someone put it in Wikipedia or something.

And you thought that those alegebra classes had no practical application. Ha!

Seeeeeeya; Goodweed of the North


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## BreezyCooking (Aug 22, 2008)

Oh for God's sake - just estimate it!!!!!

If I had to go thru all the rigamarole the rest of you are imposing I'd give up cooking all together in a heartbeat.  Why do you have to make this so utterly confusing & complicated??  We're talking about what amounts to 2 or 3 medium-size potatoes!!!!!!


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## Chief Longwind Of The North (Aug 22, 2008)

BreezyCooking said:


> Oh for God's sake - just estimate it!!!!!
> 
> If I had to go thru all the rigamarole the rest of you are imposing I'd give up cooking all together in a heartbeat. Why do you have to make this so utterly confusing & complicated?? We're talking about what amounts to 2 or 3 medium-size potatoes!!!!!!


 
That's what I'd do I'd I was actually cooking, estimate.  But the challenge was there.  I just had to take the challenge and figure it out, for the fun of it.  

Breezy, don't you jump at the occasional challenge.  It's pushups for the brain.

Seeeeeeya; Goodweed of the North


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## BreezyCooking (Aug 22, 2008)

That's all well & good, but I think the OP was just looking for an answer - not a potato-weighing think tank.

Poor Maureen - & this was her very first post here by the way - probably just left the building & gone elsewhere for a reasonable answer.  And I wouldn't blame her.  I sure would have.


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## Chief Longwind Of The North (Aug 22, 2008)

http://www.discusscooking.com/forums/members/maureen+urlaub-23849.htmlMaureen Urlaub;  I sure hope we, I, didn't scare you away.  I was just in a mood.  Usually, I will just try to help out with ordinary info.  This is really a great place, full of great people.  

If what I did was entertaining, which is what I was trying for originally, then I'm glad I did it.  If it was too over-the-top, then I apologize.

And Breezy, I know your heart is in the right place.  But we are all different.  What is funny to one person, is boring to another, or even annoying.  In the last post I made, I did give the correct answer, and with the info to maybe allow someone else to verify it.  Please take it in the spirit it was given.  And know that I am just another human on this planet who sometimes hits the mark, and sometimes misses.  I was trying to be lightheartedly academic, giving the Rube Goldberg method for finding the answer.  And if you are unfamiliar with Rube Goldberg, he was the guy who made the cartoons that showed rediculously complex mechanincal devices that performed very simple tasks.  The idea was to point out the silliness of over-complicating things.  I was trying to do the same thing with words instead of cartoons.

Seeeeeya' Goodweed of the North


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## KissTC (Aug 22, 2008)

Get a large measuring jug, one that will allow you to measure say 6 cups.

Fill with water upto the 2 cup line.

Then start putting in your cubed potato until the water comes upto the 4 cup line.

You will then have exactly 2 cups of potatoes measured.

Adjust measuring system as needed...ie you need enough water to cover all of the potatoes as any not covered in water will give a false reading.


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## pacanis (Aug 22, 2008)

KissTC said:


> Get a large measuring jug, one that will allow you to measure say 6 cups.
> 
> Fill with water upto the 2 cup line.
> 
> ...


 
Not to mention turn brown.


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## Michael in FtW (Aug 22, 2008)

Oh - geeze Louise ... _*youse guys*_ made me go dig in the garage to find my analog scales and run some tests ....

A medium sized Idaho/Irish potato (5" L x 2.5" W) weighs about 8-oz (1/2 lb). It would take 3 to make 1.5 lb. Using the water displacement method - about 1-cup per 8-oz (or 3-cups for 1.5 lbs) - but you have to measure by the water displacement method - just tossing raw potato chunks into a measuing cup will not be accurate.

So, Maureen, there is no simple answer for this - it depends on the size of the cubes and how you measure them. It's like asking the question, "How much does a cup of flour weigh?" The answer is, it depends on how you measure it.

If this is for a baking recipe - then the weight might be important ... if it is for a cookery application (potato salad, a soup, etc.) then you have a lot more leeway.

What are you trying to cook?


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## expatgirl (Aug 23, 2008)

You know.....I think some  varieties of vodkas come from potatos....maybe there should be a recipe swap......


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## Chief Longwind Of The North (Aug 24, 2008)

Michael in FtW said:


> Oh - geeze Louise ... _*youse guys*_ made me go dig in the garage to find my analog scales and run some tests ....
> 
> A medium sized Idaho/Irish potato (5" L x 2.5" W) weighs about 8-oz (1/2 lb). It would take 3 to make 1.5 lb. Using the water displacement method - about 1-cup per 8-oz (or 3-cups for 1.5 lbs) - but you have to measure by the water displacement method - just tossing raw potato chunks into a measuing cup will not be accurate.
> 
> ...



Yeh, but mine were cut so that they fit together in the cup, like pieces of a 3-D jigsaw puzzle, with no space in between them.  Just kidding, just kidding.

Maureen; I'll quit now.  I'll be good.  Honest I will.

Seeeeeeya; Goodweed of the North


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## mignon (Aug 28, 2008)

Maureen Urlaub said:


> When a recipe calls for l.5# cubed potatoes, how many cups are needed?



This is not meant to be snide, really — but can you imagine an auto repair shop without a screw driver?


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