King Arthur Light

In their place of packing, that is.  And now, in the winter, the humidity in our homes is very low, as a rule.  More often that not, I find things I weigh a little over, rather than under, though I haven't weighed the flour recently.

Dave

While I don't doubt your obvious displeasure, I think it still behooves you to check your scale against a verified weight. It's difficult for me to believe that a scale made for domestic purposes only and not for retail trade  can be expected to be accurate as a purposed scale.

Have you contacted KAF yet? The company is very conscientious about their public relations and would probably appreciate hearing about this possible fault in their goods.

It's probably within the legal margin of error.  I always weigh my butter when make buttery things and there's almost always a variation of 5-7 grams/pound block.  However, it's never in my favor!

You should really call them. I'm sure they will be shocked.

Cheer, Shuttervector

an unopened bag?  Perhaps you have one of the recalled bags that contain the little blue balls (http://www.kingarthurflour.com/voluntaryrecall/) - they might cause it to be underweight as they certainly are less dense than flour.

Hope to hear their response...

King Arthur's sales specification for their Sir Galahad (commercial name for A/P) has a stated water content of 14% maximum. In order to to that, they also need to specify a relative humidity and temperature--which I expect they would provide if asked. I'm going to guess that temperature is something like 20-25 deg C (room temperature) and the relative humidity is 70% or less. So, when they say 5 lbs on the package, they mean 5 lbs at 14% moisture, measured at 25 degC and 70% RH.

If the mill operates at 70% RH (I've never been to a flour mill, but I'd expect that at least the bigger ones have some kind of humidity control.), they will fill the bags to 5 lbs. 

If the plant RH is less than 70%, the flour may be drier and the same volume would weigh less. They could fill the bag to 5 lbs, but if the sales spec includes RH and temperature, they could fill it to something less than 5lbs and not contradict their sales specification, i.e. that volume of flour if exposed to 70% humidity would absorb moisture and gain weight.

A bag of flour filled and stored in a plant running at 70% RH, 25degC then shipped to a store and eventually ending up on a shelf at home when weighed at home should weigh less than 5 lbs because after the plant the relative humidity at all the subsequent stops is likely less than 70%--especially in any heated or air conditioned space. If given enough time to equilbrate the weight of a "5 lb" bag of flour could vary by 1-2 oz or slightly more. Of course, if the ambient humidity is greater than whatever the stated RH is at the time of packaging, the flour can gain weight.

I just weighed an unopened bag of King Arthur A/P that I have had for a couple of months and it was 78.55 oz. A bag of Gold Medal A/P of about the same age weighed 79.15 oz on the same scale. This included the bag, of course. The RH in my house is about 25-30% (yes, I have to fix my humidifier...).

There are state and federal regulations in the US regarding flour packaging & specifications.

http://www.kingarthurflour.com/professional/specifications-conventional-bakery-flour.html

Congratulations first of all on venturing into sales! I just purchased 4 bags of KA bread flour and its raining here so 100% humidity, although not in my kitchen. All my bags came in at 5 LBs .05 oz. I think instead of calculating a loss on each bag of flour you should be more concerned about unsold loaves and factoring that into the price. I sell weekly to a couple families but decided to just use a flat rate based on a market comparison by weight of local bakeries and supermarket prices. I shoot for about 50 cents ingredient cost per loaf/ pound. Make sure to consider cost of fuel/electric and your time into the cost of each loaf.

J