Extract ppg question

I was performing some density calculation in order to double check the claimed number of points per gallon for an extract.

If one pound = 454.5 grams and one gallon = 3758 grams (at room temperature), I would expect that, once the extract is added to the water, the total weight would become 454.5 + 3758 = 4212.5 grams.

Now, if I divided 4212.5 grams/3758 mL, I would get an extract concentration of 0.121 g/mL or a density of 1.121 that three times the density reported on the books (0.04 g/mL or 1.040).

If I multiply 0.121 X 3785 I get 454.7 grams = one pound. If I do the same for 0.04 X 3785 I get 151.4 g or 0.3 pounds.

I did the experiment, by dispersing one pound of DME in one gallon of water and got a density close of 1.040.

I was thinking that, this is a matter of water buoyancy (?). The same way that you (and I) weight less inside a pool full of water, maybe the dissolved molecules weights less in water.

Please let know if I am missing something.

Thanks!, Nil

Way too complicated after a few beers.

I tried to follow it, but when I found you used both grams and mL for the same number, I decided it was way too much effort to sort through it. ..... Question: Does 1 mL of water = 1 gram?

I use 36 points for LME, 45 for DME and 46 for table sugar in recipes. When I check the gravity of the wort, I find I am generally within .001 of the calculated gravity. That is good enough for me.

Calder,

The density of water is 1g/ 1mL at room temperature.

I used 40 ppg's for DME as per John Palmer's book and my personal experience. Where did you got 45 ppg's from?

Enjoy your beer...

Thanks, Nil

I've used 45 points for the longest time, but not really sure where I got it from. Just doing a quick check of a couple of sources I found:

Checking the Breiss data sheet for it's Pilsner DME, it says 1.34 lbs in a gallon = 1.060.

1/1.34 = 44.8 points per lb.

Checking BeerSmith database it lists all dry extracts as 44 points per lb.

Papazian 'Home Brewers Companion' says it varies, up to 45 points per lb.

1 lb = 453.6 grams

1 gallon of water weighs 3.78 Kg

You should NOT add one pound of extract to one gallon of water .

In fact , you should make a solution . That means , you should dissolve one pound of extract in 1/2 gallon of water and then dilute it to

one gallon by topping up .

I dissolved once 120 grams of DME in 0.5 liter of water and topped up to 1 liter . My Hydrometer read 1.046 .

Hector