Measuring Liquids

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DaWiseBrew

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So, when building out my brewhouse equipment, I installed sight glasses on the outside of the kettles. I use those sight glasses to measure liquid volume. My recipes seem to come out roughly on target for gravity, etc. I took a marked bucket from home depot, poured in 4 gallons of water into the kettle and marked the sight glass with a vinyl decal. I poured in another 4 gallons, made the mark and extrapolated the half gallon increments in between. I did this all the way up the sight glass for all 3 kettles, you get the idea.

Well, I got to thinking today that in cooking, the most accurate way to measure ingredients is weight. Ok water is 8.34 pounds per gallon at 62 F. I got out two different scales and am now finding most of my graduated buckets are off on the order of 5 to 10 percent. It seems I was slightly over-estimating the volume of water in my kettles all this time. Looks like I'll need to scratch off my vinyl decals and re-measure.

In any case, I'm curious about how everyone goes about trying to get an accurate measure of liquid volume. On your rulers, notched brewsticks, etc, how did you arrive at your baseline volume markings?
 

jtratcliff

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I used a pyrex measuring cup to measure water into a plastic gallon jug ... Marked the 1/2 gallon mark and the 1 gallon mark...

Then transferred 1 gallon at a time into my kettle and cut notches into a witness stick..

I'm sure there's at least 5-10% error in my eyeballing and sharpie marking and notch cutting...

Nature of the beast when transferring measurements ..

But I'm a bit more loosey goosey with cooking and brewing and bread making than I am in my day job...

I figure +/- 10% is acceptable for what I'm doing beer wise... I have much bigger errors to compensate for (fermentation temp control, for one) to worry about a couple percent in volume...

YMMV
 

Vale71

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Did you calibrate your scale first? If you didn't then you're just comparing different measurement errors and are none the wiser for it...
 

IslandLizard

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I use a plastic gallon container (a mayonnaise jar). It's a gallon up to where the threads start. I put marks at each quart.
That's my main measure for brewing water.
I also use a quart container with marks at each 4 oz.

Close enough for me.
 

Miraculix

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So, when building out my brewhouse equipment, I installed sight glasses on the outside of the kettles. I use those sight glasses to measure liquid volume. My recipes seem to come out roughly on target for gravity, etc. I took a marked bucket from home depot, poured in 4 gallons of water into the kettle and marked the sight glass with a vinyl decal. I poured in another 4 gallons, made the mark and extrapolated the half gallon increments in between. I did this all the way up the sight glass for all 3 kettles, you get the idea.

Well, I got to thinking today that in cooking, the most accurate way to measure ingredients is weight. Ok water is 8.34 pounds per gallon at 62 F. I got out two different scales and am now finding most of my graduated buckets are off on the order of 5 to 10 percent. It seems I was slightly over-estimating the volume of water in my kettles all this time. Looks like I'll need to scratch off my vinyl decals and re-measure.

In any case, I'm curious about how everyone goes about trying to get an accurate measure of liquid volume. On your rulers, notched brewsticks, etc, how did you arrive at your baseline volume markings?
Thanks mate for this brilliant idea. I have actually no idea how much water goes into my brewing kettle, but I got a pretty accurate bathroom scale. I'll just measure the weight! Sometimes, the simplest things don't pop up in the mind on their own...
 

jtratcliff

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Don't forget, there's also about 4% thermal expansion of water when going from room temp to boiling, if I recall correctly...

Maybe it's room temp to mash temp?

Can't quite remember, but it's another source of volumetric error...
 
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DaWiseBrew

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I figure +/- 10% is acceptable for what I'm doing beer wise... I have much bigger errors to compensate for (fermentation temp control, for one) to worry about a couple percent in volume...
True! I've been making good beer all along, so cheers to that!

Did you calibrate your scale first?
There is probably a much better way to do this. I measured 10 pounds on the kitchen scale, which has a range up to 11 pounds. Then I made sure that the bathroom scale, which has a range up to 330 pounds, agreed. Two digital scales agreeing seemed more accurate than 2 analog buckets agreeing. Actually, I have never gotten 2 analog buckets of different shapes/makes/sizes to agree, while the diverse digital scales did. That gives me some confidence. I'd probably use a NTEP certified scale and some standard reference weight if I wanted to refine this, but that seems like a future project. This is an incremental improvement for me.

I use a plastic gallon container (a mayonnaise jar). It's a gallon up to where the threads start. I put marks at each quart.
That's my main measure for brewing water.
I also use a quart container with marks at each 4 oz.
Cool, I used to do that too, but I like to be able to turn on the garden hose and fill my pots to a certain level. I find it saves me time. Also, I'm dealing with 100 quart (25 gallon) pots. Each individual measurement will introduce a little bit of error, so if I want to measure 20 gallons, that would give me an accumulation of 20 errors. Here is what I did: I used the bathroom scale to measure out a 2 larger volumes of water of six gallons each. I measured water height after the first fill, and again after the second. With those 2 benchmarks, I can then extrapolate what the other graduations (I do 1/2 gallon increments) should be.

Don't forget, there's also about 4% thermal expansion of water
Yup, measured this at 62 degrees. Water expands when heated, so a gallon of water at 168 degrees weighs less than at 62. So, the initial strike water that I then heat up will be accurate. I would then sparge until volume in the boil kettle reaches X gallons, but it must be temperature corrected gallons. Same with timing the end of the boil, you must look at the temperature corrected gallons.
 

jtratcliff

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I like to be able to turn on the garden hose and fill my pots to a certain level
That's why I use a witness stick... add a gallon to the kettle, insert long wooden dowel, cut a notch at the top of the wet mark... repeat as needed...

Then on brew day, I just turn on the water until I reach the mark I need on the stick ... I eyeball the half gallon
divisions...

The down side is that stick isn't transferable to a different kettle, unless they happen to be the same diameter...

Just last week I used my witness stick to etch volume marks onto the inside of my kettle...

So I used a 2 cup pyrex measuring cup to fill a plastic jug to 1/2 gallon and then to 1 gallon... Marked each with sharpie... Then I used the gallon jug to fill the kettle 1 gallon at a time and notched the witness stick, then used the witness stick to mark 1 gallon marks on masking tape inside the kettle, then freehand cut marks in the tape with an exacto knife, then etched with salt & vinegar...

So my error propagation was probably pretty bad...:p.
 
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DaWiseBrew

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then etched with salt & vinegar...
I've been wanting to try that! Even though I have sight glasses, it still seems pretty cool! Do you worry at all about wearing away the etchings with bar keepers friend?
 

jtratcliff

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I've been wanting to try that! Even though I have sight glasses, it still seems pretty cool! Do you worry at all about wearing away the etchings with bar keepers friend?
My kettle is Aluminum, so it's darkened from the oxide layer anyway.... I don't typically scrub with anything more than a nylon brush so as not to mess up the oxide layer... I etched right thru the oxide (i.e. didn't scrub shiny first) and you can physically feel the etched markings.

I haven't brewed with it since I etched, so I don't know how the markings will hold up ... or stand out against the kettle wall once they oxidize... It was pretty straight forward to do, though. I used an old 5v wall wart that I had laying around as my power source... I didn't hear any of the sizzling that some mention when using 9V or 12V, but it worked... I just kept gong back and forth over my stencils until it was nice and shiny... Went thru about 3-4 qtips to mark 9 individual gallon marks and numbers... Probably took less than hour to place all the masking (used electrical tape), xfer the gallon marks from witness stick, cut the gallon marks in the masking tape, position the number stencils, and then perform the etching.
 

Dr_Jeff

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I used the stick method as well, marked my mash paddle, one tool two uses, burned the marks in with a soldering iron.
Then never used it for that more than a couple of times.

I use keggles, they are 15.5 gallons. Half of that is 7.75 gallons, the center weld. The ridges are roughly a third of the way up from each end, so the lower one is roughly five gallons, the upper one is ten gallons, fill, look, guesstimate from there. when I boil, it is usually down around the top of the top ridge, good enough for me.

I know it's not what you were looking for, but my method seems to work pretty good for me.
I don't bother with a refractometer or a hydrometer anymore either, although I have both.
 

Birrofilo

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In any case, I'm curious about how everyone goes about trying to get an accurate measure of liquid volume. On your rulers, notched brewsticks, etc, how did you arrive at your baseline volume markings?
Some time ago I compared the volume markings of my kitchen 1 litre plastic measuring jar, a laboratory 200ml Pyrex jar and a generic 1 litre Pyrex jar. They were not very in accordance with each other. I don't remember exactly but the difference between the extremes was something like 5% (!).

So when I decided that I needed a precise way to measure the volume in my kettle (which has inner markings but they are way off) and that I had to make a birrometro, I wanted something pretty precise because this is something that I want to do once for good, and with no afterthoughs about how precise is the measuring.

I weighted 1kg tap water and I noticed where the water arrived in my kitchen 1 litre plastic measuring jar. Let's say that the water arrived 2mm above the 1 litre mark. I used that measure (2mm above the mark) for all subsequent pourings into the kettle.

From litre 10 on, and at every 2-litre interval, I waited for the waves to stabilize and I took a measurement with a "sharpie" on the back of the birrometro which I use for my fermenters and distilling kettle.

This is satisfactorily precise. Small errors are due to the inherent imprecision in sharpie marks, sight alignement with the piece of the kettle where I take the mark, precision of the sitting of the metal on the level of the wort. But, overall, I think this was a decent method, and certainly more precise than using one of my not-very-precise jars.

I then made the markings permanent with the method which I read in another thread, using salt and vinegar and a 9V battery.
 
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DaWiseBrew

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Honestly, this is a good way, and I'd think probably on par with my measurements of weight for accuracy. I had the added complexity of marking a sight glass external to the vessel, and I wasn't certain as to the thickness of the bottom of the kettle.

I weighted 1kg tap water and I noticed where the water arrived in my kitchen 1 litre plastic measuring jar.
Love the metric system. 1 kg = 1 liter (at least at 4 degrees C).

In general I agree that this is a decent approach. For precision, I think you must have the proper dimensions of your system, or use weight. I don't know of an affordable measuring vessel that is reliable. I would want to minimize the number of pours and measurements performed.
 

jtratcliff

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The Priceless Calculator (Priceless Brew in a Bag Calculator) also gives inches per gallon for a given kettle diameter... kettle diameter is set bottom left under Equipment ... Gallon height is given upper right under General Results...

Lots of other useful goodies there, too, of course.... Including temperature adjusted volumes and height in kettle for strike water, pre-boil, post boil, etc...
 

Birrofilo

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Love the metric system. 1 kg = 1 liter (at least at 4 degrees C).

In general I agree that this is a decent approach. For precision, I think you must have the proper dimensions of your system, or use weight. I don't know of an affordable measuring vessel that is reliable. I would want to minimize the number of pours and measurements performed.
The deviation from the 1 kg / 1 litre rule for water is insignificant for our kind of purposes.
E.g. at 20 °C (ambient temperature) the density goes down to 0,9982071 g/cmc. We insert many mistakes in our measuring which are much larger.

Beer might behave differently but, again, presumably close enough.

A measuring stick (birrometro) is a very practical solution. You only need to do the weighting "once". Also, it is more comfortable to use that marking the inner side of the kettle. When the stick touches the wort (without being immersed in it) you take the reading on the top of the kettle, and if you have no good light, you just put a finger in in the stick and go where you have good light.

In theory I could have taken the dimension of the kettle (it's easy, it's only one measure to take, the inner diameter) and calculated the height on the measuring stick. But that would not take into account the volume in the recirculation pipe (besides irregularities in shape).

Also, if you need better precision I think it is possible to buy a scale which can be calibrated and which can weight 1 kg to the decigram, which is 1/10.000 of mistake more or less (plus the imprecision of the scale, which is on the same small order).

If you measure a kettle which has let's say a 30 cm diameter, you would need a meter able to measure to the 0,03 mm or 30 microns for the same degree of accuracy and you don't have that precision nor a meter which can be calibrated.
 
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DaWiseBrew

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Anyone use the Digiten flow meter? Short Circuited Brewers did a video on it below... Looks like once its calibrated would be a great solution to get exact measurements on the fly.

Digiten DFC15 Liquid Flow Controller -Installation, Setup, and Accuracy Test
I haven't done much research on flow meters, but have been curious about it, especially in the context of brewery automation. Getting into a scripted brew day with a control screen, etc., is definitely on my long term to do list.

This guy has flow meters connected to his system:
 
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