Gravity Samples

The Homebrew Forum

Help Support The Homebrew Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

dlowe1992

Well-Known Member
Supporting Member
Joined
Sep 20, 2023
Messages
151
Reaction score
201
Location
Telford
22A39DBF-BCDF-4A14-A733-E2E73D55E003.jpeg


Hi all,

Mid brew day here in Telford..
When I take pre boil and post boil gravity samples, I’m getting a bit of ‘stuff’ in my samples, and I suspect it’s playing havoc with my readings as they tend to be higher than expected.

Do others note this?
Should I try to avoid collecting any matter?
Or am I making higher gravity wort than expected?m
Eg todays brew I’m aiming for a pre boil gravity of 1.035 and getting 1.040..
No great matter, but would lrefer to correct if I’m taking them wrong…

🤷‍♂️🤷‍♂️🤣🤣
 
(What's this? A chink in the impenetrable "hydrometer" fad. I've got to take advantage of this ... ).

(Cough ... ).

What you need...

...is a Pyknometer!

Seriously, they are the bee's knees, you'll never go ...

(... Hoy! Put me down you lot. This most undignified. What do you think you're doing? Noooo ... not the river again ...).
 
(What's this? A chink in the impenetrable "hydrometer" fad. I've got to take advantage of this ... ).

(Cough ... ).

What you need...

...is a Pyknometer!

Seriously, they are the bee's knees, you'll never go ...

(... Hoy! Put me down you lot. This most undignified. What do you think you're doing? Noooo ... not the river again ...).

Now that wasn’t the answer I was expecting…
Dare I ask what pyknometer is? 🙈🙈
 
Perhaps your efficiency has changed?
Mine went from high 60s to high 70s with water treatment, changing the bazooka to a custom copper manifold in the tun,maintaining sparge water temp and taking more care sparging....or that's what I'm blaming.
 
Perhaps your efficiency has changed?
Mine went from high 60s to high 70s with water treatment, changing the bazooka to a custom copper manifold in the tun,maintaining sparge water temp and taking more care sparging....or that's what I'm blaming.

Well I’ve had a play around and I think I had a few errors on Brewfather when formulating my recipe. Having corrected it all in line with what I actually did, it would appear I hit the PBG and OG pretty much on the nose!!

Happy days!!
 
That "stuff" is normal. It's the cold break (and possibly small bits of hop etc).

It won't affect your gravity readings
 
Now that wasn’t the answer I was expecting…
Dare I ask what pycnometer is? 🙈🙈
Ha! I'm in! I just have to reel in me catch now ... actually, not now, it's late and I'm off to bed.

Well you might hide your eyes ... cover your ears too. You should have asked @Buffers brewery, you can see his "reaction" to your post ... too late!

Tonight I will answer your question "what is a pyknometer?" ... that's easy, it's a bottle with a hole in the stopper (for allowing your spell checker to change the "k" into a sissy "c", you are picked out for "special treatment"!). But before I go, here's a piccie of a big bottle on weighing scales. I normally use 25ml bottles, but you can trick the scales with a 100ml bottle, and this one has a sample reading "1.0445" (SG, or "relative density", just ignore the decimal place on the scales). And, yes, there are four decimal places in that example, not boring old three.

20220901_193005_WEB.jpg


Now, I need to go quick. i don't want another dunking in the river (flippin' Philistines!).
 
Pyknometers: Part 2 (only 5673 parts to go!).

Shocking. I said I'd do a proper post next day and here we are two days on and I've done ... nothing!

Let me kill off another myth 😈

Brewers were not unable to measure the sugar content of their beer worts before the hydrometer (saccharometer) came along in the latter part of the 18th C. It was a PITA but the larger breweries would have certainly bothered to do it. The give-away is the units of measurement: "Pounds per Barrel" and the like, a density measurement involving weights and volumes, not a buoyancy measurement as would be native to a hydrometer (which works on the far more complex principal of "a solid suspended in a fluid is buoyed by a force equal to the weight of the fluid displaced by the submerged part of the suspended solid" 😵‍💫 ).

And the "hydrometer" pinched the well-known known later scale used: "Specific Gravity" ... no idea what that phrase means, but it's the same as "Relative Density". Relative to ... well, water of course. Weigh a sample of water, then using the same container (and therefore identical volume) weigh a sample of beer or beer wort. The unit of weight is immaterial, that's say the water weighed 5.670 "Peebees" and the wort weighed 5.897 "Peebees". Don't care about the temperature, as long as both samples are the same temperature (been hanging around in the same shed). Now divide the weight of wort with the weight of water (i.e. we'll have the weight of wort as it relates to the weight of water) ...

1.040

Remarkable! And so, we have the "Relative Density" (SG) of our wort. As a ratio (with water), at any temperature (within reason) and weighed in any units of mass (SG is a ratio and therefore has no units). So why did hydrometers become so popular? Convenience! Few had the equipment and time to weigh samples of water and wort so accurately. And so, we get the myth that brewers couldn't measure the amount of sugar in their worts. What they "couldn't" do is they "couldn't be ar***d"!

The "convenience" argument held until very recently (and I mean within the last decade). These days electronic scales have become fairly reliable ... and cheap! I don't mean the postage-stamp sized "drug-dealer" scales for a tenner or two ... they are about as reliable as the "drug-dealers"; but the "midi-sized" scales which can be easily recalibrated with calibration weights and fairly good down to one-hundredth of a gram (they have stabilising routines which do sometimes make themselves known), not perfect but quite good enough to produce SG results with four decimal places. And better things will surely come along very soon.


A little trick. Instead of weighing wort in the example above, divide the weight of water (5.670 Peebees) with itself. Any number above zero divided by itself is ... one! So, the SG of water is ... one! Or 1.000 ... exactly. Slightly confusingly, at 4°C, 1cm³ of water weighs one gram (very nearly exactly). A density of 1.000 g/cm³ (or g/ml). If working with SI measurement units and SG it's easy to get mixed up (I've been there) ... don't!


That'll do for now. The rules are simple. If I can't hear you all writhing on the floor crying out in pain as you tear your hair out ... I'll just write some more until I can.
 
Last edited:
Is "well water" heavier then? Minerals or just cos its further down?
Than? Never mind ... of course it is, it wouldn't stay in the bottom of the hole otherwise.

Seriously (that'd make a change) some of the most mineral rich well water in UK comes from Burton-on-Trent (ignoring undrinkable "hot" springs and spas) and may will contain about 1000-2000 parts-per-million dissolved solids. That's an enormous 0.1-0.2%! how much difference to density of the water is that going to make?

(Measurable ... but I did start the response with "seriously", and many people do not consider it being "serious" to measure SG to four decimal places, let alone ... gawd knows how many?).

And water at the bottom of a well is heavier, but once it's lifted to the surface it ain't (the water never got heavier, the column of air above it did). That's why there is "mass" and "weight", you don't want something silly like "gravity" mucking things up.
 
Pyknometers: Part 2 (only 5673 parts to go!).

Shocking. I said I'd do a proper post next day and here we are two days on and I've done ... nothing!

Let me kill off another myth 😈

Brewers were not unable to measure the sugar content of their beer worts before the hydrometer (saccharometer) came along in the latter part of the 18th C. It was a PITA but the larger breweries would have certainly bothered to do it. The give-away is the units of measurement: "Pounds per Barrel" and the like, a density measurement involving weights and volumes, not a buoyancy measurement as would be native to a hydrometer (which works on the far more complex principal of "a solid suspended in a fluid is buoyed by a force equal to the weight of the fluid displaced by the submerged part of the suspended solid" 😵‍💫 ).

And the "hydrometer" pinched the well-known known later scale used: "Specific Gravity" ... no idea what that phrase means, but it's the same as "Relative Density". Relative to ... well water of course. Weigh a sample of water, then using the same container (and therefore identical volume) weigh a sample of beer or beer wort. The unit of weight is immaterial, that's say the water weighed 5.670 "Peebees" and the wort weighed 5.897 "Peebees". Don't care about the temperature, as long as both samples are the same temperature (been hanging around in the same shed). Now divide the weight of wort with the weight of water (i.e. we'll have the weight of wort as it relates to the weight of water) ...

1.040

Remarkable! And so, we have the "Relative Density" (SG) of our wort. As a ratio (with water), at any temperature (within reason) and weighed in any units of mass (SG is a ratio and therefore has no units). So why did hydrometers become so popular? Convenience! Few had the equipment and time to weigh samples of water and wort so accurately. And so, we get the myth that brewers couldn't measure the amount of sugar in their worts. What they "couldn't" do is they "couldn't be ar***d"!

The "convenience" argument held until very recently (and I mean within the last decade). These days electronic scales have become fairly reliable ... and cheap! I don't mean the postage-stamp sized "drug-dealer" scales for a tenner or two ... they are about as reliable as the "drug-dealers"; but the "midi-sized" scales which can be easily recalibrated with calibration weights and fairly good down to one-hundredth of a gram (they have stabilising routines which do sometimes make themselves known), not perfect but quite good enough to produce SG results with four decimal places. And better things will surely come along very soon.


A little trick. Instead of weighing wort in the example above, divide the weight of water (5.670 Peebees) with itself. Any number above zero divided by itself is ... one! So, the SG of water is ... one! Or 1.000 ... exactly. Slightly confusingly, at 4°C, 1cm³ of water weighs one gram (very nearly exactly). A density of 1.000 g/cm³ (or g/ml). If working with SI measurement units and SG it's easy to get mixed up (I've been there) ... don't!


That'll do for now. The rules are simple. If I can't hear you all writhing on the floor crying out in pain as you tear your hair out ... I'll just write some more until I can.
I was wondering how those things worked. Now I know.athumb..

Sticking to the rules, though, I'm writhing on the floor, crying in pain (no hair to pull out).
 
... some of the most mineral rich well water in UK comes from Burton-on-Trent ...
I was reading up a bit on Burton and its Gypsum. And, like I do, get distracted from the key subject ... BEER!

Gypsum is a hazardous stuff to have under your house. It dissolves! Slowly, but results in land collapses, etc. But that wasn't the most distracting! Gypsum is valuable enough to want to dig it out. And if you have vast caverns underground and there's a war on ... it's a wonderful place to stash loads of High Explosive ordnance. And it's what they did near Burton. Some 4,000 tons of the stuff.

Great ... until someone was a bit clumsy with a hammer.

The hole in the ground is still there (err ... Big?). Fortunately, it wasn't a very habitated area, though a bunch of cows didn't come off too well.

Look it up ... the Fauld Crater.
 
Pyknometers: Part 2 (only 5673 parts to go!).

Shocking. I said I'd do a proper post next day and here we are two days on and I've done ... nothing!

Let me kill off another myth 😈

Brewers were not unable to measure the sugar content of their beer worts before the hydrometer (saccharometer) came along in the latter part of the 18th C. It was a PITA but the larger breweries would have certainly bothered to do it. The give-away is the units of measurement: "Pounds per Barrel" and the like, a density measurement involving weights and volumes, not a buoyancy measurement as would be native to a hydrometer (which works on the far more complex principal of "a solid suspended in a fluid is buoyed by a force equal to the weight of the fluid displaced by the submerged part of the suspended solid" 😵‍💫 ).

And the "hydrometer" pinched the well-known known later scale used: "Specific Gravity" ... no idea what that phrase means, but it's the same as "Relative Density". Relative to ... well, water of course. Weigh a sample of water, then using the same container (and therefore identical volume) weigh a sample of beer or beer wort. The unit of weight is immaterial, that's say the water weighed 5.670 "Peebees" and the wort weighed 5.897 "Peebees". Don't care about the temperature, as long as both samples are the same temperature (been hanging around in the same shed). Now divide the weight of wort with the weight of water (i.e. we'll have the weight of wort as it relates to the weight of water) ...

1.040

Remarkable! And so, we have the "Relative Density" (SG) of our wort. As a ratio (with water), at any temperature (within reason) and weighed in any units of mass (SG is a ratio and therefore has no units). So why did hydrometers become so popular? Convenience! Few had the equipment and time to weigh samples of water and wort so accurately. And so, we get the myth that brewers couldn't measure the amount of sugar in their worts. What they "couldn't" do is they "couldn't be ar***d"!

The "convenience" argument held until very recently (and I mean within the last decade). These days electronic scales have become fairly reliable ... and cheap! I don't mean the postage-stamp sized "drug-dealer" scales for a tenner or two ... they are about as reliable as the "drug-dealers"; but the "midi-sized" scales which can be easily recalibrated with calibration weights and fairly good down to one-hundredth of a gram (they have stabilising routines which do sometimes make themselves known), not perfect but quite good enough to produce SG results with four decimal places. And better things will surely come along very soon.


A little trick. Instead of weighing wort in the example above, divide the weight of water (5.670 Peebees) with itself. Any number above zero divided by itself is ... one! So, the SG of water is ... one! Or 1.000 ... exactly. Slightly confusingly, at 4°C, 1cm³ of water weighs one gram (very nearly exactly). A density of 1.000 g/cm³ (or g/ml). If working with SI measurement units and SG it's easy to get mixed up (I've been there) ... don't!


That'll do for now. The rules are simple. If I can't hear you all writhing on the floor crying out in pain as you tear your hair out ... I'll just write some more until I can.


Well you can consider me on the floor crying in anguish. If nothing else, beer brewing is getting a little too close to dreaded Science lessons for my liking.... :laugh8: :laugh8:

Ah well, beer will help... :beer1:
 

Latest posts

Back
Top