ACADEMIC QUESTION: S.G, soluability, physics OR Why am I stupid?

[woozy]

At sea level and normal atmospheric pressure a pound is a pound. Has nothing to do with the density of the material.

Of course not. But a gallon is a gallon. A gallon of lead is heavier than a gallon of feathers because a 1) lead is denser than feathers and 2) a gallon is the same volume as a gallon.

A gallon of water (with a density of 8 lbs/gallon) weighs eight lbs. A gallon of sugar water (with a s.g. of 1.046 => a density of 1.046 times that of water => a density of 8.368 lbs/gallon) wieghs 8.368 lbs.

If the *volume* is fixed, weight is proportional to density. ("denser stuff is heavier")

Likewise if the *weight* is fixed, volume is inversely proportion to density. ("denser stuff is smaller")

And if *density* is fixed weight and volume are proportional. ("Bigger stuff is heavier and heavier stuff is bigger")

 

[masterfool101]

With all due respect to everything that has been discussed, I'm going to try to take this back to the beginning for a second.

Obviously I have a misconception somewhere. But where?

This are my conceptions; one (or more) of them must be wrong:

1. A specific gravity reading is ratio between the density of liquid compared to the density of water (calibrated for a specific temp. but lets not bog ourselves down). Thus, for example, if a solution has an s.g. of 1.046 that means the solution is 1.046 times as dense as water.

True, for True Specific Density. (I'll explain later what I mean by that)

2. Density is mass/volume. Weight is measure of gravity on a mass and in this case can be considered synonamous with mass so density is (on earth at sea level) also a measurement of weight/volume.

Not quite, but this has been discussed to death. I won't go into it. Yet.

3. Thus: a gallon of something with an s.g. of 1.046 will be 1.046 times as heavy as a gallon of water.

Yes, except this is APPARENT specific gravity, which has to do with weight, and not densities. Again, it is of minor importance.

4. A gallon of water weighs 8 lbs so a gallon of something with an s.g of 1.046 will weigh 8.368 lbs.

Truth be told, THIS IS YOUR BIGGEST PROBLEM. Water is NOT 8 lbs/gal. At 70 Degrees F, water is 8.329 lbs/gallon. At 60 Deg F, it is 8.338 lbs/gallon.

Because WATER VOLUME IS TEMPERATURE DEPENDENT, it is highly important to know the temperature of the water. Now, for most measurements, at or near room temperature, I recommend using 8.33 (going one more decimal point assumes a level of confidence that you just won't have!) - which is pretty valid for everything between about 65 Deg F and 75 Deg F.

5. Soluable means disolves in water thus adding it to water will not increase the volume.

Not true. Discussed previously. Volume will slightly increase.

6. Sugar is soluable in water thus added a pound of sugar to a gallon of water will result is one gallon of solution.

The trick is to put a pound of sugar in a gallon container, then add water (mixing as it goes up) to get to 1 gallon. THEN you will have 1 gallon of SOLUTION.

7. Sugar has a diastatic power of 46 PPG which means adding 1 lb of sugar to one gallon of water will yield a solution with a s.g. of 1.046

As mentioned before, it's not "diastatic power" . . . that's a measure of enzyme activity in malts. It's simply the formula used to calculate the SG of the SOLUTION. 46 points per pound per gallon, where a "point" is .001 added to the SG.

8. Thus 1 lb of sugar added to a gallon of water will be one gallon in volume and thus weigh 8.368 lbs.

As was pointed out, this is incorrect. Technically, 1 lb sugar added to one gallon of water would, at 70 Deg F, weigh 9.33 lbs (mass is unchanging). However, what you want is the weight of 1 gallon of SOLUTION, which would be 8.33 * 1.046 = 8.71 lbs.

9. Adding a lb of sugar to a gallon of water causes no chemical of physical reaction that will result in any loss of mass or weight.

At least, not that you can detect in the volumes you're dealing with and with the equipment you have

10. 1 lb of sugar weighs a lb. A gallon of water weighs 8 lbs so mixing the two results in a solution weighing 9 lbs.

Not true, for all of the reasons discussed above.

11. 9 lbs is a different weight than 8.368 lbs

This is certainly true!

Which of my conceptions is wrong?

A few of them

 

[Bookworm]

And I am not sure where to begin with this.

The gravitational pull on an object on this planet (ie the weight of the object) is in NO way, shape or form affected by altitude.
No, no, no.

You should begin with a very basic understanding of physics.

Yes, yes, yes yes it is. But it is summer break and I do not want to write up and teach a physics lesson today.

 

[Weezy]

yeah, you walked off the cliff at 5 (and #2 is poorly phrased but not inaccurate). thanks for playing tho.

 

[woozy]

Truth be told, THIS IS YOUR BIGGEST PROBLEM. Water is NOT 8 lbs/gal. At 70 Degrees F, water is 8.329 lbs/gallon. At 60 Deg F, it is 8.338 lbs/gallon.

*This* is the biggest problem? Nonsense.

Whether a gallon of water weighs 8 lbs, 8.3 lbs, 64 lbs, or some unknown variable x or *any* value _other_ than 7.368 lbs/gallon then adding a pound of sugar will make it a pound heavier and calculating while assuming volume stays the same will lead to the same error that *whatever* + 1 does not equal 8.368.

If I correct to 8.329 or 8.338 I'll end up with 9.329 and 9.338 does not equal 8.368. This can hardly be called the "BIGGEST PROBLEM".

#5 _is_ the crux and heart of the matter.

 

[woozy]

yeah, you walked off the cliff at 5 (and #2 is poorly phrased but not inaccurate). thanks for playing tho.

I'll have to find that article I read a few months ago that in discussing calculatng S.G. and adding extracts very strongly implied it was sugar's soluability in water that allowed you to ignore volumes. Maybe the article was implying something else entirely but stupid me; I assumed that if they knew more about beer than I do they must know more about chemistry than I do. (Which isn't hard as I know very little about chemistry. But until *this* most things I knew about chemistry were simply incomplete rather than outright wrong.)

You should begin with a very basic understanding of physics.

Yes, yes, yes yes it is. But it is summer break and I do not want to write up and teach a physics lesson today.

weight at sea level = F = GMm/R^2 < GMm/(R + alt)^2 = weight at altitude alt. (R is radius of earth; 3,959 miles. M is mass of earth. m is body's mass. G gravitational constant.)

Thus your weight at 1 mile of altitude will be 3959^2/3960^2 = 15673681/15681600 = 0.999495 of your weight at sea level.

 

[ACbrewer]

I'll have to find that article I read a few months ago that in discussing calculatng S.G. and adding extracts very strongly implied it was sugar's soluability in water that allowed you to ignore volumes. Maybe the article was implying something else entirely but stupid me; I assumed that if they knew more about beer than I do they must know more about chemistry than I do. (Which isn't hard as I know very little about chemistry. But until *this* most things I knew about chemistry were simply incomplete rather than outright wrong.)

This link has already been posted, but I'm bringing it back. What I found about this link http://winemaking.jackkeller.net/hydrom.asp interesting is that at 1.045 gravity, sugar added to water is listed as 1lb .07 oz, and the volume added is 1gal, 10.4oz. the 10.4oz is the added volume from the sugar. Sugar itself is taking up 1 part in 13 of the volume (138.4 fld oz). If you measured the sugar I think it is about 1.5 to 2 cups - this is all the air in the sugar - from the crystal shapes etc., and the fact that the sugar and water molecules can get a bit closer with each other, than seperately.

Someone also mentioned mixing 50ml/50ml water and alcohol and said you wouldn't end up with 100ml. Well nor would we end up with 50ml.

weight at sea level = F = GMm/R^2 < GMm/(R + alt)^2 = weight at altitude alt. (R is radius of earth; 3,959 miles. M is mass of earth. m is body's mass. G gravitational constant.)

Thus your weight at 1 mile of altitude will be 3959^2/3960^2 = 15673681/15681600 = 0.999495 of your weight at sea level.

I personally would have used SI units, but yes, this is correct, being further from the center of the earth changes the weight, although given it is -.0005 or .05%, it can be ignored. I mean seriously at what point does the delta from a altitude difference matter.

The air pressure for those making beer in Denver is more important, as boiling is lower, and thus isomerization is harder. - I read an article at byo.com on brewing at the south pole (8000-9000 foot above sea level) and the author stated that the boiling temp was only about 190F because of the reduced preasure. sorry OT.

 

[woozy]

If I were to rewrite the beginning not knowing any more then than I did but anticipating these nit-picking comments I'd have written something like "Density can be seen a a measure of weight per volume because for the purposes of brewing beer on planet earth mass is proportional to weight (and even uses the same units)"

The fact that weight is less at higher altitudes is merely an interesting tidbit and in response to someone saying altitude has nothing to do with weight. (Which *practically* it doesn't, but this was the same person who took exception to my stating that mass and weight are "equivalent".) At what point does the delta from an altitude difference matter? Well, not till you start reaching the outer stratosphere scores or hundreds of miles up. But at those heights, as I stated, it's hard to perceive weight when there isn't any floor to measure against.

[After all, the moon *is* falling and does have weight. Actually the moon "weighs" the same as the earth, doesn't it. A neat little trick of semantics which ultimately means nothing. ... hmmm, maybe not... The moon has a weight when one measures earth's gravitational pull on it that the is the same weight of the earth when measuring the moon's gravitational pull on it but to say two things "weigh the same" we pretty much have to mean when measured against the same gravitational pull, wouldn't we. So the whole thing is semantically meaningless.]

[Heh, heh. The earth weighs 225 lbs! When measured in my gravitational pull...]

I *think* the gravity at antarctica will be theoretically higher than at the equater do to planetary bulge. But I could... goes to google ... no the equatorial bulge is about 26 miles which overcomes the 9000 feet altitude. But the gravitational tides have more of an effect.

I don't think air pressure could have any effect on measuring specific gravity.

Off topic but interesting and the original topic was exhausted in the very second post.

 

[evrose]

If I were to rewrite the beginning not knowing any more then than I did but anticipating these nit-picking comments

Seriously? Nit-picking? You started a thread asking an "Academic question". You got "Academic answers". When it comes to academia and science, the devil is in the details. If you wanted a general feeling, you shouldn't have started trying to talk math and science. geesh.

I really need to stop being so stubborn and start LISTENING to what people are telling you here. There is a great learning opportunity here. There are a lot of really bright people who have chimed in on this thread trying to help you... and to be honest, your attitude has been... less than optimal. Criticizing detailed discussion as "nit-picking" is but one example.

I'd have written something like "Density can be seen a a measure of weight per volume because for the purposes of brewing beer on planet earth mass is proportional to weight (and even uses the same units)"

Ugh... the difference between mass and weight has been explained in this thread, so I won't bother to repeat it. If you want to start understanding the science, you have to start thinking like a scientist... which means you have to start using terms like a scientist. Saying, "oh well, it's close enough" is a bad baseline attitude. again... geesh.

The fact that weight is less at higher altitudes is merely an interesting tidbit and in response to someone saying altitude has nothing to do with weight.

Actually, it has everything to do with weight.

Edit: I must be drunk... and it's still before noon. Yikes.

[After all, the moon *is* falling and does have weight. Actually the moon "weighs" the same as the earth, doesn't it. A neat little trick of semantics which ultimately means nothing. ... hmmm, maybe not... The moon has a weight when one measures earth's gravitational pull on it that the is the same weight of the earth when measuring the moon's gravitational pull on it but to say two things "weigh the same" we pretty much have to mean when measured against the same gravitational pull, wouldn't we. So the whole thing is semantically meaningless.]

Holy wow Batman... I can't even start to unravel that. And I can't be bothered with the rest of this... it's makes my head hurt trying to read it...

I need a beer.

 

[Johnnyhitch1]

Why is this not in brew science?!?!

HEY LADY!!! Your scaring the kids!!!

 

[motobrewer]

As far as dissolving it in water goes, the overall mass of the water/sugar increases, but the amount of space (volume) that is taken up is pretty is EXACTLY the same as the volume of the water did.

i have dissolved a lot of sugar in a lot of water, and this is innaccurate.

In my experience, if you have 8 oz weight of water(~8oz volume, or 1 cup), and put 8oz weight of cane sugar in it, you will have roughly 12oz volume of solution.

 

[evrose]

i have dissolved a lot of sugar in a lot of water, and this is innaccurate.

In my experience, if you have 8 oz weight of water(~8oz volume, or 1 cup), and put 8oz weight of cane sugar in it, you will have roughly 12oz volume of solution.

Volume(final) = Volume(water) + Volume(sugar)

Because there is airspace in the gaps between the sugar grains, it may not look like that. But if you did the math properly, using the mass and density of each component, that's what you'd see.

 

[ACbrewer]

Seriously? Nit-picking? You started a thread asking an "Academic question". You got "Academic answers".
Actually, it has everything to do with weight. Really, when you're calculating the amounts of stuff to use in brewing, you're always dealing with MASS. MASS MASS MASS MASS MASS.

MASS.

Always.

I need a beer.

So then you use a blance scale in your brewhouse? With calibrated masses to balance with? Because othewise, you adding pounds or newtons or weight kg, NOT mass kg. Except for a balance scale, we use weight when measuring or more accurately, the scales measure weights, not masses. And yes we all need a beer now.

 

[Bookworm]

Most of the nit picking answers and information given are not precisely correct, including mine. But without getting into mass spheres, bond angels, dipoles, and a lot of other complicated stuff they are more than close enough for beer.

EDIT: Maybe we could ask Stephen Hawking if he can work on a unified theory of beer but I doubt if it would be much less complicated than coming up with a unified theory of physics.

 

[evrose]

So then you use a blance scale in your brewhouse? With calibrated masses to balance with? Because othewise, you adding pounds or newtons or weight kg, NOT mass kg. Except for a balance scale, we use weight when measuring or more accurately, the scales measure weights, not masses. And yes we all need a beer now.

Oh Bloody *#&#$... It was too early in the morning when I typed that, and by coffee hadn't circulated. Point conceded.

I guess my overriding point to the OP is to STOP confusing the issue. He's making this entire thing more complicated than it needs to be... and frankly, is being a bit stubborn.

I'm going to find that beer...

 

[woozy]

Ugh... the difference between mass and weight has been explained in this thread, so I won't bother to repeat it. If you want to start understanding the science, you have to start thinking like a scientist... which means you have to start using terms like a scientist. Saying, "oh well, it's close enough" is a bad baseline attitude. again... geesh.

Everyone with a high-school education ought to know the difference between mass and weight. Are you telling me that density because it is mass/volume can't possibly be used to measure weight/volume because weight and mass are different things and therefore can't possibly be co-related? Then I question who does and doesn't understand the difference between mass and weight.

My one and only claim and only claim that had anything whatsoever to do with mass was that if a solution has a gravity of 1.046 then a) the solution is 1.046 denser than water b) a volume unit of the solution is 1.046 times heavier than a volume unit of water and c) a volume unit of the solution is 1.046 times more massive than a volume unit of water; and as long as we are on the planet earth (or anywhere else with a consistent gravity) the three statements are equivalent. (i.e. given any one you can conclude the other two)

Are you claiming that that is not true?

Actually, it has everything to do with weight.

That's what I said. It was someone else who said it didn't.

Holy wow Batman... I can't even start to unravel that. And I can't be bothered with the rest of this... it's makes my head hurt trying to read it...

It's all true and accurate. The moon *is* falling. That's what being in orbit is. [falling: moving under the influence of gravity.] And the moon has a "weight" of GMm/R^2 (where G is the gravitational constant; M the mass of the earth; m the mass of the moon; and R the distance between their centers). This is equal to the "weight" of the earth under the moon's gravity.

So then you use a blance scale in your brewhouse? With calibrated masses to balance with? Because othewise, you adding pounds or newtons or weight kg, NOT mass kg. Except for a balance scale, we use weight when measuring or more accurately, the scales measure weights, not masses. And yes we all need a beer now.

*THANK* you!

Oh Bloody *#&#$... It was too early in the morning when I typed that, and by coffee hadn't circulated. Point conceded.

I guess my overriding point to the OP is to STOP confusing the issue. He's making this entire thing more complicated than it needs to be... and frankly, is being a bit stubborn.

I'm going to find that beer...

Confusing *what* issue?

The issue was resolved in the very *second* post when it was pointed out the volumes increase when adding sugar.

And that was *it*. End of story.

*I* am not the one who brought up any red herrings about the difference between mass and weight. ("red herring" and "nit-picking" because i) the concepts where never confused in the original post and ii) any hypothetical misunderstanding of the concepts were not pertainent to the reasoning of the the original post and would not, in this case, have led to the false conclusion.)

 

[woozy]

*My* point is that I'm willing to concede that I was stupid enough the not know what the meaning of soluable was. And that was damn stupid. It was so damned stupid that I'm not willing to blame myself solely and instead am going to blame some indefinate article (pun not intended) that lead me astray. Partially. I was stupid for letting it lead me astray when I should have known better.

But I'm *not* willing to concede that I ever misunderstood the difference between mass and weight even when I used the unfortunate (but still true) phrase "can be considered synonamous" and certainly not that I misused the terms in any way that would have led to a false conclusion.

And in that I am stubborn.

 

[evrose]

I'm going to open a 2008 Stone RIS. This thread has made that a necessity.

 

[Doongie]

Sugar has a diastatic power of 0.

Diastatic power is a measure of enzyme activity.

This ^^^^^

 

[woozy]

This ^^^^^ (diastatic meaning)

Yes. Yes. I acknowledge I used on incorrect terminology. And I'm grateful to have the correction. I'm still unsure of the proper term for "PPGage", that is the gravity factor of sugar.

Nonetheless improper terminology didn't contribute to any faulty conclusion.