Quote:
Originally Posted by saibot
If you have a container filled with large blueberries there will be more empty space between them than if you have tiny blueberries, so it will weigh less. But of course moisture content will make a difference too. If they all look to be about the same size, one package may be older and starting to dry out a little bit, and that will make it lighter.
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Ugh. I was hoping to avoid this. The weight vs. size issue is a LOT more complicated than that. I won't say that you are wrong, but I will say you are sometimes wrong (and sometimes right, if that is any solace).
In math terms, this is a packing or stacking issue. There seems to be agreement that there are no absolute answers in most such problems.
An ideal blueberry is a sphere. Quoting from this page:
https://puzzling.stackexchange.com/q...fit-in-the-box
"The optimal pattern of packing spheres is pretty well known, not as widely known is the fact that this pattern has 7 different orientations where the spheres are all organised in layers of simple patterns. In four of these orientations the spheres are aligned in a triangular pattern, in the three other planes they are aligned in a square pattern. The key to this puzzle is to rotate the pattern so that the wasted space along the sides of the box is minimised."
The exact inner dimensions of the container can affect packing. As an example, if you had a couple giant blueberries that were 3/4 of the size of the dry pint container, only ONE could fit inside. The volume of the sphere of that one blueberry would be less than the total volume of many blueberries a tenth the size packed in the same container.
If the container dimensions are off just enough that optimal packing is impossible of a particular blueberry diameter, the container will be lighter than one that fits the packing. THat can go either way, with larger blueberries winning out, or smaller ones being able to pack better and have more overall mass.
Continuing, if you have ever decanted coffee or flour from a large container to a smaller one, you have seen how you can get much more of those products into the container if you shake or tap it when filling. What you are doing is helping the material into a more optimal packing. The same happens with blueberries. If the packing process doesn't have a shaker, the container will be light.
Then the issue that blueberries are NOT perfect spheres, but varying shapes and sizes (within a certain range) and can have bits of stem and leaves intermixed, throwing "optimal packing" out the window.
The bottom line is that with a dry pint, the weights will vary. When you pick out one, you want to look at the product much more than judge by weight. A pint that is heavy may have smashed berries on the bottom, or there could be mold beginning, or that container may have been recently rinsed with water swelling the cardboard. OTOH, if the container is excessively light, there may be other problems.
As an aside - now you know why professional bakers ALWAYS go by ingredient weight and never by dry measure.