# Weights & Measures & Calibration



## alexia (Mar 3, 2002)

I would like to hear how you all assure yourself that your measuring implements are accurate. When a recent rhubarb pie bubbled over, I decided to check my equipment to see if I had mismeasured any of the ingredients because of it. I'm mostly concerned about this issue when I bake and am in a higher state of anxiety about precision.

What I found is that a couple of my measuring cups were off in that they did not match each other (one was off 25 ml). Fortunately for dry ingredients I have a triple beam scale that I can use as my reference point when necessary, but it's a pain to set the tare so I have a Salton for ordinary use. How do you recalibrate an electronic scale such as a Salton if it needs it. I don't see anything on it that allows for readjustment.

And as far as dry measurements are concerned, the weight:volume ratio changes with the item. A Tbs or cup of sugar will not weigh the same as corn starch. So how do you determine that the cups and spoons you are using are accurate. What is your reference point. When I have a recipe that gives weight and volume measurements, there is no problem, I just follow the weights. But most American recipes are given in volume and I don't have that option.

Lastly, to broach a subject that leaves me totally in the dark. I understand some of the British measurements are different from US and Continental. Could someone straighten me out on that?


----------



## phatch (Mar 29, 2002)

It's easy to calibrate in metric. 1 liter of water weighs exactly one kilo (2.2 pounds) by definition. Plus the tare of your container. Check that with, say, the butcher's scale first as they're usually well calibrated.

If your scale converts to the US system, you can check it first in metric and convert from volume to weight with water and milliliters. A calcuator with conversions built in is good too.

Unfortunately, in the US system, a liquid oz of water isn't 1 oz of weight, it's a bit more.

Once you've got a baseline, you can convert to volume or weight from the accurate baseline with the substance used in your baseline.
Phil


----------



## kokopuffs (Aug 4, 2000)

Go to either VWR (Van Waters and Rogers) or Scientific Products; they sell standard weights which ARE THE ULTIMATE IN CALIBRATION. Trust me - 4 years of college chemistry

I purchased a brand new Ohaus Triple Beam and thanks to standard weights, one of the poises tested inaccurate: after zeroing the scale, a poise showed 8.5 grams with a standard 10 gram weight placed into the pan. The exchange was prompt, let me tell you.

Get you own set of standard weights for they're inarguable.


----------



## jock (Dec 4, 2001)

Weight measures are the same all over the world - a pound is a pound and a gram is a gram anywhere. Liquid volume can change though and Alexia is right, it is different in Britain. Here a pint of liquid is 16 fl oz; in Britain it is 20 fl oz. 
There are no standard spoon measures in Britain either. A teaspoon is litterly that - the spoon with which you stir your tea. A table spoon is like a desert spoon and there may or may not be a correlation between the two. Recipes will call for a heaped teaspoon of (whatever) or a rounded tablespoon. Home cooks just know because they just do! It does make it a bit akward for anybody not raised there trying to follow a recipe.
By and large, I don't get too hung up on being super accurate with weights and measures. If a slight variation in the end product results from slightly inaccurate measures and the product is still good, it has become unique to you and is all the better for it. IMHO

:bounce: :bounce: 

Jock


----------



## kokopuffs (Aug 4, 2000)

Weights are a standard. By using them, differences in the final product can be made predictable. Standardization is more easily achieved by using weight than by using volume measurements.


----------



## kuan (Jun 11, 2001)

What's temperature setting 5 in Britain?  Here again I repeat my plea. METRIC PLEASE!

Kuan


----------



## jock (Dec 4, 2001)

Approximately 375 degrees. They only have these settings on gas ovens. I don't know who invented the system but whoever it was deserves to spend eternity in the oven set at gas mark 9.

Jock


----------



## jock (Dec 4, 2001)

Sorry kuan, you asked for metric. That would 190 degrees centigrade.

Jock


----------



## mudbug (Dec 30, 1999)

alexia,

Some insight you may find interesting:

*Flour:* Always sift your flour no matter what type you buy. It is proven that _when measured by "volume"_ sifted flour will weigh more consistently when sifted as opposed to not sifted before use in a recipe. This is not applicable for measuring only by weight.

Weights and Measures Conversion Calculator Very handy in a pinch. Quantities may even be entered using fractions if required.

*Measuring Oven Accuracy* There is a wonderful article in the March 2002 issue of Cook's Illustrated. It discusses the calibration of ovens both of commercial quality and residential use and the wide variations between each oven, how they heat in what areas of the oven, how they "maintain" the target temperature, and the differences which leads to the issue of thermometers.

They end up rating thermometers and highly recommend an inexpensive oven thermometer over high priced ones.

*Measuring Thermometers:*
*Boiling Water Test *

The most common way to test a thermometer is to place it in boiling water. An accurate thermometer will read about 212*F in boiling water at sea level under normal atmospheric conditions.

To test your thermometer, bring a pot of water to a vigorous boil. Hold the thermometer stem or probe in the water, making sure not to touch the sides or bottom of the pot, and take your reading.

Remember that there are several factors that affect the boiling point of water:

*As atmospheric pressure decreases, the boiling point decreases. Atmospheric pressure will vary depending on your altitude and local weather conditions. 
*Hard water boils at a temperature 1-2*F higher than soft water, due to dissolved mineral salts. 
*Using a tall, narrow pot will result in a boiling point about 1*F higher than a short, wide pot.

If you live at high altitude, you'll need to take that into account when testing your thermometer. The table below lists the approximate boiling point for a number of different altitudes. As a general rule, the boiling point decreases approximately 1.8*F for every 1000-foot increase in altitude. Note that the actual boiling point may be higher or lower depending upon atmospheric pressure in your area on any given day.

AltitudeBoiling Point (F/C) 
Sea Level212/100 
2,000 ft.208/98 
5,000 ft.203/95 
7,500 ft.198/92 
10,000 ft.194/90 
15,000 ft.185/85 
30,000 ft.158/70

Another way to determine your boiling point is to use a Boiling Point Calculator. By entering your current barometric pressure and your elevation, you can get a good estimate of your boiling point.

As for recalibration for your Salton electronic scale, use the appropriate e-mail address indicated in the user manual that came with your product or contact them directly with your questions.

Using standard size dry measuring cups, gently spoon ingredients into the measuring cup. When the container is full, level off with a knife. Scooping or tapping a measuring cup will pack the ingredients, and there will be more than is required in the cup. This extra amount could affect the balance of the recipe. Level dry ingredients with a knife.

Weigh the measurement with your scale and write it down on your recipe or keep notebook, journal or software file where you log the ingredients you use and how much say 1 Tbls of "cornstarch" weighs. If your recipe comes out correctly, the next time you use your scale and need one tablespoon of cornstarch, you won't have to break out your measuring spoon.

Also, you can just keep adding to the "like" ingredients on your scale by zeroing out between each ingredient and this will save you on the number of items you'd normally have for clean up.


----------



## alexia (Mar 3, 2002)

I want to thank everyone for their very helpful information. 

Jock is right that one's own way of measuring can bring about good results and may be what makes one's version of a dish different from others' (my pinch or handful is different from yours & original measurements were for the most part based on one's body parts). I'm pretty casual about amounts when I am cooking savory and will often alter recipes even the first time I try them, but when I bake I get really paranoid, obsessive. Particularly the first time I use a recipe. Of course the most careful measuring in the world does not protect against what I did the other day: substituted some carefully measured baking soda for cornstarch in a pie - dumb, dumb, dumb. (I keep them both in labled glass jars instead of original boxes). 

cchiu, great tips, but one thing puzzles me. I understand why one would sift flour even when measuring by weight as it could easily effect the texture of baked goods, but I don't understand how it can alter the weight itself. Clumps of flour harbor moisture? As for the rest it makes great sense and I will follow some of your suggestions. 

BTW: for those of you who prefer a mercury oven thermometer to the spring type, rush out and get one while they're still available. Taylor is discontinuing them and in some states they are now illegal, though more accurate. 

And for the "reading glass set" the thermopan digital instant read has great big numbers that don't require glasses.


----------



## mudbug (Dec 30, 1999)

alexia,

Allow me to clarify... Where this _does_ apply is measuring by volume. If you measure a cup of unstifted flour with a one cup measuring cup five times, and weigh it each time and log the final weight, your results will be far more varied than if you measure five times and sift each time. Measuring dry ingredients by _volume_ can be a problem due to the type of flour, humidity, and whether or not it is sifted can affect the amount of flour actually used. Sifted or not, one pound of flour will consistently be one pound of flour.

You may find the following very informative:

*Weighing vs Measuring Ingredients *

*Weighting to measure *

*How to Buy a Digital Scale *

*When a Cup is not a Cup*

*Digitals Top Instant-Read Thermometer*


----------



## alexia (Mar 3, 2002)

Thanks for the clarification and the site references, cchiu`. 

Since I've begun baking more in the last couple years, I've treated myself to a Salton scale to replace the old spring type that did very well for chicken and potatoes but was utterly useless for a half lb of flour, much less 100 g of chocolate. I'm completely convinced that measuring by weight is preferable to measuring by volume. I find myself getting annoyed that the Salton goes in increments of 5 g/ 1/4 oz.

The vexation comes when one has a US recipe written with a "cup" of flour. Some writers use the scoop and swipe method, others the sift three times and measure, etc. And while I usually read the intro in cookbooks and can know what standard that writer is using in that book (assuming I can remember), the frustration mounts when finding a recipe in a magazine, on a website, etc. Why are US cookbook writers so resistant to at least including weight measurements in their recipes. I understand it's unlikely an average US cook will have a scale in the kitchen, but what I can't understand is why. It makes everything so much easier. I also wish we'd go metric soon. The little bit of initial adjustment to metrics would be more than compensated by the easier arithmetic.

The funny thing is that other than baking or trying out a new recipe, I mostly cook by sight, feel, and taste. It's a handful of this, a pinch of that, taste and adjust. Baking still sends me into spasms of anxiety.


----------



## jock (Dec 4, 2001)

One thing I have noticed about recipes is that some say "X" cups of flour, sifted and others say "X" cups of sifted flour. The flour will weigh more in the first case than in the second. You have to be sure of the source though because if it is a poorly written recipe, it will say one thing but mean the other.

Jock


----------



## alexia (Mar 3, 2002)

Jock, you're right about sifted flour/flour sifted, and sometimes they don't even say sifted. I know that there are some basic ratios of ingredients for the different kinds of cakes to obtain particular results with them, but I don't have enough experience with baking to be able to look at a recipe and know whether it will work or figure out what the recipe writer meant to say.

With cooking it's different. When I look at a recipe I can pretty well tell whether it will work and tweak the technique if it needs it. Baking is another matter.


----------



## jock (Dec 4, 2001)

Alexia, sounds like you and I are in the same boat - that's exactly my experience.  

Jock


----------

