Question about gravity and sediments

[Jokester]

We calculate starting gravity with a bunch of particulates in the wort.
But by the time we finish all of it has settled along with the dead yeast.
That sediment is removed right ? even in an unfiltered beer, that sediment isn't mixed up right ?
The FG calculations are for the "clear beer" on top right ?

Thanks.
Srinath.

 

[kh54s10]

Gravity readings are measurements of sugar content in the wort then beer. Sediment doesn't affect that unless there is so much that the hydrometer can't float.

 

[balrog]

I often wondered the same thing about all the break material in the OG measurment

So I tested. And after waiting an interminable time, must've been 3 or 4 beers worth, when the OG hydrometer sample cleared almost completely, lo and behold, same SG measurement in the clear sample as the first cloudy particulated break material laden sample. Then I had another beer.

 

[odie]

I always wondered about that myself...now I know...

 

[Jokester]

From the laws of physics its not possible really. The sediment drops to the bottom because it has a higher specific gravity (also known as density) than the surrounding material.
A hydrometer measures specific gravity, no sugar content is mechanically measurable unless you boil out all the liquid scrape the left overs, dry it up and weigh it.
Dropping sediment in the final beer will lower the specific gravity reading. Maybe they assume that has been removed - as in 1.065 to 1.01 involves .002 worth of sediment so when someone enters 1.01 it calculates it as 1.012 to add sediment back into the beer.

However my question was poorly framed, so let me reframe it - and it may be a question for the mr good beer calculator designer.

The OG with particulates floating around is what they would assume, because no one would sediment that before checking.
We put in an FG where sediment has occoured, and no one stirs it up into the beer before checking FG - is that their assumption as well.
An analysis of their calculator would tell me if they have a dummy dead number for sediment or some how do something other than 7 to 4 conversion and convert it to abv from abw.

Cool.
Srinath.

 

[Jokester]

Doing a sediment before OG measurement is a bit misleading, some of that sediment may be eaten by the yeast. Is it likely something that was dissolved and not sedimentable not be eaten b ythe yeast and as the SG drops by turning some of it into alcohol, that drops out as a sediment ? Maybe. Ofcourse all these are errors too small, or in some cases cancel each other out resulting in an accuracy that is within the margin of error - needless to say we measure only in the whole graduations, if its between 2 its another inaccuracy we're getting.

Needless to say, the density of the sediment is very very close to that of the surrounding beer, that's why it takes so long to settle.

Cool.
Srinath.

 

[balrog]

And then there's the whole "measure with a refractometer" to measure sugar (et al) content

 

[Jokester]

Refractometer measures refractive index of the liquid. Can be a good indicator of sugar content. As sugar turns to alcohol, the refractive index rises I guess, sugar is higher than water, ethanol is 1.36 to waters 1.33 and sugar water at 10% which is 1.34. Yikes, how do these work ? I should experiment with mine, maybe put vodka in it. BTW I need to try my hydrometer in vodka as well, will I get the entire thing drowned in vodka ?

Cool.
Srinath.

 

[Jokester]

Water is 1.33, 10% sugar water by weight is 1.3478, 10% by weight ethanol is 1.3395, and when 10% sugar solution is all turned to ethanol which would be just under 6% abw, refractive index will be 1.3367 but about 3% sugar by weight will also be 1.3367. I cant believe it will be able to tell the difference between a set of numbers that close together, but if you ferment a 10% by weight sugar solution dry a refractometer will read that as a 3% or so solution. Maybe you're supposed to have that information ready when you check FGs' for these things.

Cool.
Srinath.

 

[Miraculix]

I often wondered the same thing about all the break material in the OG measurment

So I tested. And after waiting an interminable time, must've been 3 or 4 beers worth, when the OG hydrometer sample cleared almost completely, lo and behold, same SG measurement in the clear sample as the first cloudy particulated break material laden sample. Then I had another beer.

I did the same test and had big differences between the settled and the non settled sample. I waited the whole night.

 

[Jokester]

I did the same test and had big differences between the settled and the non settled sample. I waited the whole night.

This I would expect. I don't know but mrgoodbeers calculator needs to be analyzed. Sediment is removed in most finished beers, and never so in most worts and removing it in the wort anyway is a pointless test, there is plenty that will sediment in wort that can be eaten by yeast. What gets it to settle is density, what yeast eats is a biological reaction, it doesn't care if the material is tightly packed or loose. So a gravity reading to alcohol conversion will be off and it is lower alcohol than you measure due to the denser sediment dropping out of the picture.

Cool.
Srinath.

 

[Alex4mula]

I don't understand. If you know all the theory why you ask? I guess then everybody is measuring wrong because I never read that you need to remove sediment out of vial to measure OG. This is how most of my beers look at OG time. Carboy first pics if when I take the sample after just being filled. Second pic is how it looks about 30min later. I have left the hydrometer in the tube while I clean and sediment drops but OG stays the same.

 

[kh54s10]

All the discussion is IMO, pointless. The OG sample is taken right after the boil. No one that I have ever heard about removes the sediment at this time. So, any OG measurements have the sediment in them.

My next brew, I am going to test this. I will fill my sample cylinder, take a reading, let the sediment settle, pour the liquid off of the sediment and return to the cleaned cylinder for another measurement. I suspect any change would be insignificant.

 

[grampamark]

I always let the OG sample sit on the counter while I rack the beer to the fermenter and then clean the BK. By the time I get around to putting the hydrometer in the test cylinder there’s a layer of sediment at the bottom and the sample is clear.

Unless someone can make a plausible argument that the sediment is somehow pushing up on the beer, I think I’m getting a reasonably accurate gravity reading.

 

[Miraculix]

I don't understand. If you know all the theory why you ask? I guess then everybody is measuring wrong because I never read that you need to remove sediment out of vial to measure OG. This is how most of my beers look at OG time. Carboy first pics if when I take the sample after just being filled. Second pic is how it looks about 30min later. I have left the hydrometer in the tube while I clean and sediment drops but OG stays the same.

View attachment 656918 View attachment 656919 View attachment 656920

So the sediment dropped onto the hydrometer. Next time, measure gravity instantly, make a note, remove the hydrometer, wait over night, measure again. ... Difference!

 

[Miraculix]

But to be fair, I don't remove hot break or cold break and have cloudy wort, so my sediment might play a bigger role than the sediment of others.

 

[davidabcd]

This is the kind of thread you read from the bottom.

 

[davidabcd]

Just intuitively, aren't the suspended particles in the OG sample just being affected by the general density of the wort and not causing an increased density? What percentage of the volume do these particulates make up, anyway? I don't seem them having anything more than a minor effect. Again, intuitively, I don't think these particulates equate to what, say, salt does when it dissolves thoroughly in solution.
My main thought though is, as long as there is a standard method for measuring, does it actually matter? In other words, there's really no need to get too significant.
Edit: All that any new brewer really needs to know is that when sugar is converted to alcohol by the yeast, the hydrometer sinks. When the hydrometer stops sinking when verified by a measurement two or three days apart, your beautiful beer is finished. No need to overthink it.

 

[Jokester]

OK guys, I am the flunkie that got 30% in the exam. That 30% seems to be the part the 70% students missed.
I'll just say - hydrometer isn't a anything but a density measuring device.
The refractometer measures refractive index.
Let me start comparing one to the other and see where it goes OK.

Cool.
Srinath.

 

[JimRausch]

I can't believe I've read through the whole thread and no one pointed out that a hydrometer measures DISSOLVED solutes in solution. Sugar are dissolved, as are any salts. But the sediment? Not dissolved by defintion, therefore it does not affect a gravity reading.

 

[kh54s10]

I can't believe I've read through the whole thread and no one pointed out that a hydrometer measures DISSOLVED solutes in solution. Sugar are dissolved, as are any salts. But the sediment? Not dissolved by defintion, therefore it does not affect a gravity reading.

I didn't point out this because Chemistry classes were a long, long, long, time ago....

 

[bracconiere]

hydrometer only measures things that dissolve....damn i see jim beat me too it now.....

 

[Robert65]

Particulates that have buoyancy will apply a significant upward force on a hydrometer. It's the same principle as a life preserver. This effect will be augmented in the case of suspended yeast cells which are also contributing both CO2 -- rising bubbles are critical factor I haven't seen addressed here -- and nucleation sites for same, in addition to their own buoyancy. Yes, hydrometers are designed to measure only density of solute. But they can only give an accurate reading in a fully degassed and clarified sample, where the other variables are eliminated.

 

[Miraculix]

I can't believe I've read through the whole thread and no one pointed out that a hydrometer measures DISSOLVED solutes in solution. Sugar are dissolved, as are any salts. But the sediment? Not dissolved by defintion, therefore it does not affect a gravity reading.

I once saw a show about the Bermuda triangle. They claimed to know why boats are disappearing there, they said it is because of methane eruptions underneath the sea. The methane is being released in the form of small bubbles which lower the average gravity of the water, so that ships are no longer swimming.

They showed experiments where they basically had a boat floating on water and than releasing small bubbles underneath it. The result was that the boat sank.

Those bubbles are also not solved in the solution but they lower the average gravity of the space that is being replaced by the boat in the water. If the average gravity of this space gets lower than the average gravity of the boat, than the boat sinks.

Same applies to particles and the hydrometer.

 

[balrog]

If SG measurement was significantly affected by break material suspended in the sample, not bubbles which would provide buoyancy, then my OG readings with 2 hydrometers would not match my readings at that time with that sample on refractometer I should think. They do. I no longer worry about it. I still measure OG with all three instruments. I also straighten carpet fringe but not in an obsessive way. My toothbrush does not have to line up due North on the bathroom shelf either. Most of the time.

[Edit: Sorry Mom, "if SG measurement *WERE* significantly affected"]

 

[Alex4mula]

I can't believe I've read through the whole thread and no one pointed out that a hydrometer measures DISSOLVED solutes in solution. Sugar are dissolved, as are any salts. But the sediment? Not dissolved by defintion, therefore it does not affect a gravity reading.

Exactly. Some post here are really funny. If you have pebbles at the bottom it will not affect anything. Unless they are Fruty Pebbles which could add some nice sugar to the mix :-D

 

[Jokester]

OK so sediment out or in makes no difference to gravity ? Now does the yeast have an ability to eat what will be the sediment in the wort stage ? I can then see where sediment adds to alcohol without figuring in the OG reading.
I am not being argumentative, just trying to correct some error I might be seeing in my fermenting of beer.
Thanks.
Srinath.

 

[Miraculix]

OK so sediment out or in makes no difference to gravity ? Now does the yeast have an ability to eat what will be the sediment in the wort stage ? I can then see where sediment adds to alcohol without figuring in the OG reading.
I am not being argumentative, just trying to correct some error I might be seeing in my fermenting of beer.
Thanks.
Srinath.

Just check it for yourself. For me, it made a difference, and the difference was not small. Just be sure to remove the hydrometer from the sample that you leave to settle out and to keep the temperature the same.

 

[Robert65]

I did some experiments once with dry bakers yeast in water. I found that yeast in suspension at what I estimated to be about the cell count of beer in active fermentation added about 0.004 sp. gr. to a hydrometer reading over water at the same temperature. I have no idea whether my materials and methods were valid.

 

[Jokester]

Just check it for yourself. For me, it made a difference, and the difference was not small. Just be sure to remove the hydrometer from the sample that you leave to settle out and to keep the temperature the same.

Preaching to the choir here man, fat when churned out of milk raises the SG of the left over milk. Fat really isn't soluble in water based medium like milk, else it cant be churned out. So I'm gonna say dissolved or otherwise, it affects density.
Cool.
Srinath.

 

[ncbrewer]

I'm a retired mining engineer. Heavy media separation is sometimes used to separate minerals by specific gravity. From https://www.911metallurgist.com/blog/dense-heavy-medium-separation-hms-dms: "Since most of the liquids used in the laboratory are expensive or toxic, the dense medium used in industrial separations is a thick suspension, or pulp, of some heavy solid in water, which behaves as a heavy liquid."

For this method to work, the solids must be very fine so that it stays in suspension long enough for the separation to take place. This is the same effect as floating a hydrometer in wort that has very fine yeast suspended - the water with yeast acts as a heavy liquid. I have no idea what the overall specific gravity increase with yeast in water would be - probably extremely small. But the principle is valid.

 

[Saunassa]

On top of all this what I read as 1.050 might be read as 1.052 using the hygrometer. It is all subjective to the person and their eyes. Maybe we need to add a centrifuge to our list of 'necessary' equipment. One more thing to geek out about.

 

[Jokester]

It would be more vital on the FG side, because 0.99 vs .988 etc is more dry by almost 300% less sugar. Yea parallax and margin of eyeball error is huge.
Cool.
Srinath.

 

[bracconiere]

Fat really isn't soluble in water based medium like milk

i believe emulsifiers are the reason?

 

[Jokester]

Well milk has a whole mess of protein and sugars like lactose that will keep fat suspended in the colloid that is milk. However, mechanically separating fat makes it a basic not dissolved, just there along with type of suspension. Yea emulsion - not for fat, but the rest of milk can not be mechanically separated - you need to break it with rennet or lemon or acetic acid etc. or bacteria etc.
So milk is a colloid or emulsion (just a colloid with 2 liquids) but fat is just there in the mix, held in by some minimal cohesion, mechanically disturb it by beating it and gravity takes over and floats up.
Sorry trying to remember 9th grade chemistry/physics here. Not googled up now. So some errors may be present.
Cool.
Srinath.

 

[Jokester]

I guess milk is a colloid - From annenbergs chemistry learner - https://www.learner.org/courses/che...s=U&num=Ym5WdElUQS9PU289&sec=YzJWaklUQS9NaW89

A solution is more than just a homogenous mixture. It is a homogenous mixture down to the molecular level. So, even if it looks homogeneous to the human eye, there can still be groups of molecules clumped together that make it not a solution. Homogenized milk isn't a solution. Rather, it is a colloid—a mixture in which very small particles of one substance are distributed evenly throughout another substance. The clumps of fat in the milk, while small, are still in groups of fat molecules. If individual fat molecules were uniformly spread throughout the milk, homogenized milk would be a solution.

I guess by whipping it, we get the fat globules to collide (hey is that why its called a collide ??? LOL.) and they break their protein bonds free and join up with other fat and there on gravity takes up and they float up.

Cool.
Srinath.

 

[6Tap]

What about the friction factor on the glass hydrometer submerged in a solution of varying size and density particulate matter that will constantly change with brew process, ingredients, type of minerals in the water, temperate, and gravitational pull based on sample location from the equator?

 

[Robert65]

What about the friction factor on the glass hydrometer submerged in a solution of varying size and density particulate matter that will constantly change with brew process, ingredients, type of minerals in the water, temperate, and gravitational pull based on sample location from the equator?

I can't tell if you're being serious or just taking the piss, I still "liked" your post. Either way.