Weight of Water

I'm about to brew my third batch (Chinook IPA) from Northern Brewer. I realized it required a 5.57 gallon boil size. Curious to know how to measure out exactly 5.57 gallons, I searched the forum and came across a thread mentioning professional breweries measure water by weight. The more I read, this approach seemed logical and most accurate.

Because I can't offer much in advise as I'm so new to brewing, I thought I would share the bench scale I found as a way to contribute for those who are interested.

http://tinyurl.com/bwhg2h6

This seems to be a nice scale for the price. Low profile and decent size foot print seems like it would have enough surface area to support a bucket or brew pot. The 150lb version reads with a little more accuracy than the one capable of reading 400 lbs. 150 lb read would easily weigh 5 gallons plus the weight of the brew pot.

According to the thread and some additional research my math works out to needing 46.5095 lbs of water for a 5.57 boil size. Plus the weight of the brew pot.

Anyway, I found this interesting and the ideal method for nailing boil size. The scale seems like it would be perfect for the home brewer. When I learn more about brewing, perhaps I can contribute something more useful.

BillyRaygun said:

Anyway, I found this interesting and the ideal method for nailing boil size.

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First of all, Relax. Then, DWHAHB. Unless you are conducting a rigorous scientific experiment, there is no reason to be measuring your pre-boil volume to an accuracy of hundredths of gallons. You don't even know how much you will lose during the boil!

Now, if you do know from experience how much you typically lose during the boil, fine. But a printed recipe sheet is useless for telling you that.

So, RDWHAHB. Cheers!

No scientific experiment, but don't I want to get in the habit of being consistent? What if I make a great batch and want to repeat it over and over again? Regardless of yield, but for the purposes of consistent taste, wouldn't I want to know as accurately as possible my steps so I could duplicate it whenever I want as often as I want?

True but round things off, even to the nearest .5 gallons using a calibrated stick. You don't want to be lugging 50+ pounds of wort around and if you go all grain you would have to run off while the kettle sat on the scale to stop sparging at the right time.

Get close on the pre-boil volume, then boil down to your post boil gravity because that's the number that's import. Your boil time will vary based on humidity, outside air temp, pre-boil volume, etc. but when you hit that post-boil OG you are where you want to be. If you boiled off more volume to get there, note it to make adjustments in the recipe, then tweak with DME and water to get the post-boil OG and volume you want.

I believe water weighs 8lbs per gallon.

As to the more important lesson of this thread, you don't have to be overly accurate with 'the numbers' to reproduce batches that taste exactly the same.

8.33 lbs per gallon but who's counting

Meanwhile, the rest of the world says 1 liter of water = 1 kilogram.

8.34 pounds per gallon

A pint is a pound the world around

Blackfish said:

A pint is a pound the world around

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A rolling kettle gathers no Irish Moss.

A gallon is a volume measurment = 231 cubic inches for a U.S. gallon. The weight of a gallon of water depends on the temperature of that water - water expands as it heats up by about 4% from room temperature to boiling. One U.S. gallon at room temp. weighs about 8 1/3 pounds and at boiling it weighs about 8 pounds.

DeafSmith said:

A gallon is a volume measurment = 231 cubic inches for a U.S. gallon. The weight of a gallon of water depends on the temperature of that water - water expands as it heats up by about 4% from room temperature to boiling. One U.S. gallon at room temp. weighs about 8 1/3 pounds and at boiling it weighs about 8 pounds.

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For this reason, measuring water (and, really, all your ingredients) by weight is going to be the easiest way to obtain a truly repeatable result. This is independent of quixotically trying to shoot for 0.2% accuracy on the boil volume.

In terms of repeatability, though, it's probably not worth worrying about small changes in the amount of boiling water until you've controlled a lot more variables. How confident are you that your AA% for your hops is accurate to 1% (i.e., are those hops 10.4% AA or 10.5% AA? That's a 1% difference) Is your grain crush exactly the same as before?

Beer production just can't be controlled to that level of accuracy. Even the big guys who do everything they can to produce exactly the same product in each batch still blend individual batches to maintain their overall quality (or so I've been led to believe).

I think 0.5 gallons (about 10%) is probably slightly too big to call undetectable, but if you can measure to 0.1 gallon (2%) accuracy, I will confidently say that there is absolutely no reason to be more accurate than that. At that point, the temperature and humidity in your kitchen (or whereever) are probably at least as important as the exact quantity of water.

I just fill each of my vessels with a premeasured amount of water (I try to fill it over half way, but in full gallon increments, so an 8gallon kettle might get 6 Gallons of water), then I stick a clean tape measure in the water and figure out that in my 8G kettle, a gallon is 1.5" of water. In my 10G kettles (2 different brands) it's 1.55" for a gallon. When I'm brewing I use the tape measure for mash lauter purposes, and from there on I don't have to measure anymore because my preboil volume accounts for everything else (equipment losses, cooling shrinkage, etc...).

another point if measuring pre-boil water to that degree of accuracy for repeatability is completely useless unless you measure humidity, atmospheric pressure and ambient room temperature and recreate all of those as well because they will effect amount of boil off and even efficiency of your burner.

jbaysurfer said:

I just fill each of my vessels with a premeasured amount of water (I try to fill it over half way, but in full gallon increments, so an 8gallon kettle might get 6 Gallons of water), then I stick a clean tape measure in the water and figure out that in my 8G kettle, a gallon is 1.5" of water. In my 10G kettles (2 different brands) it's 1.55" for a gallon. When I'm brewing I use the tape measure for mash lauter purposes, and from there on I don't have to measure anymore because my preboil volume accounts for everything else (equipment losses, cooling shrinkage, etc...).

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I did a similar thing. I marked half-gallon increments on each fermenter starting at 1 gallon. For my kettle, I added half gallons at a time (I think) and measured the depth. It's not quite cylindrical at the bottom, but is at the top. Since I don't ever bother measuring small quantities, I just know the depth to 2 or 3 gallons, and then know how many gallons per inch above that.

It's probably good to 0.1-0.2 gallons, which is plenty good for me. Heck, I'm happy if my mash efficiency is repeatable within 10%...

I'm not trying to make this more complex then it needs to be. I simply wanted to measure 5.57 gallons of water with some degree of accuracy. For my own peace of mind and to teach myself consistency.

I'm doing a brewery tour in October and I will ask the professionals how they measure out water and to what degree of accuracy. Would a professional brewery really take the time to calculate humidity, water temperature, etc.? I guess it wouldn't surprise me if they did, but from the LakeFront Brewery tour in Milwaukee, I didn't get the sense they have a climate controlled environment of any kind for weighing/measuring water.

I completely understand there are other factors that play a role in accuracy. But as a starting point, for my own comfort, couldn't weighing 5.57 gallons of water, even using the measuring tape or graduated stick method discussed here, at least be a starting point of accuracy?

I like the measuring tape/graduated stick concept the more I think about it. Seems a lot easier then lugging around 40 plus pounds of water.

Cheers!
Billy Raygun

BillyRaygun said:

No scientific experiment, but don't I want to get in the habit of being consistent? What if I make a great batch and want to repeat it over and over again? Regardless of yield, but for the purposes of consistent taste, wouldn't I want to know as accurately as possible my steps so I could duplicate it whenever I want as often as I want?

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You can duplicate it without using exactly the same amount if water. There are other things that will have a greater impact.

Brew by numbers. Bulk blend for busch like consistency.

It's interesting what different people geek out on. I totally geeked out on learning to harvest and count yeast cells. As far as water I just round to the nearest 1/8 gallon using a 2 quart pitcher with measurements on the side. Weighing water seems futile but it really is a smart way to hit an exact number.

JonM said:

Meanwhile, the rest of the world says 1 liter of water = 1 kilogram.

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Ya really. If you're going to weigh the water, do yourself a big favor and switch to metric.

8.35 lbs per gallon. Or at least that's what they taught us in fire academy.

BillyRaygun said:

I'm not trying to make this more complex then it needs to be. I simply wanted to measure 5.57 gallons of water with some degree of accuracy. For my own peace of mind and to teach myself consistency.

I'm doing a brewery tour in October and I will ask the professionals how they measure out water and to what degree of accuracy. Would a professional brewery really take the time to calculate humidity, water temperature, etc.? I guess it wouldn't surprise me if they did, but from the LakeFront Brewery tour in Milwaukee, I didn't get the sense they have a climate controlled environment of any kind for weighing/measuring water.

I completely understand there are other factors that play a role in accuracy. But as a starting point, for my own comfort, couldn't weighing 5.57 gallons of water, even using the measuring tape or graduated stick method discussed here, at least be a starting point of accuracy?

I like the measuring tape/graduated stick concept the more I think about it. Seems a lot easier then lugging around 40 plus pounds of water.

Cheers!
Billy Raygun

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In short, yes, the pros will do it as accurately as they can, but that's because their costs are much more significant than ours.

The fast answer is 5.57 gallons of water weighs 46.4358 lbs. However, you're asking about a boil volume.

Take the SG of the wort and multiply that by the weight above. That will get you your final weight.

Or just fill your boil kettle to a little over 5.5 gallons and call it good.

As said before, until you know what your boil off is gonna be, you can't be that precise. There are multiple factors for your boil volume: evaporation rate, kettle geometry, boil time, strength of boil, and more. You gotta get a feel for the equipment before going for overly precise measurements.

Blackfish said:

A pint is a pound the world around

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Untrue
A pint glass is a drinking vessel made to hold either a British ("imperial") pint of 20 imperial fluid ounces (568*mL) or an American pint of 16 US fluid ounces (473*mL). These glasses are used predominantly to serve beer.

kylevester said:

The fast answer is 5.57 gallons of water weighs 46.4358 lbs.

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Except when it's 46.4822 lbs or when it's 46.3925 lbs (fresh out of the fridge, or at 70°F room temperature, respectively)...

If you have a scale that can hold your brew kettle and you don't mind hoisting it around, going by weight instead of volume sounds like a great idea. But for repeatability I don't see a reason to worry about 5.57 vs 5.5 or 5.6 gallons. For the first batch, put in 5.5 gallons or a bit more and weigh it. Or just pick a weight in the ballpark of 46.4 pounds. In the future, go with that weight.

The problem with 5.57 gallons (well, not really a problem, but the reason it's needlessly precise) is that it's just way more precise than the rest of the system. Even recipes aren't precise to that level---bitterness formulas, abv calculations, color formulas, etc, are all fairly rough approximations that aren't accurate to 1% in most cases. These are in addition to the various things pointed out above. So you can make a case that you may benefit from hitting exactly the same starting quantity of water---at least you make absolutely sure it's not changing---but exactly what that quantity is doesn't matter relative to what your recipe/calculations tell you.

Shooting for repeatability is a great idea, and going by weight instead of volume is actually a pretty nice idea. I wouldn't do it to get greater precision or accuracy, but it sounds like it could be easier than measuring volume, given the right scale.

And, finally, doing what you're after isn't going to hurt anything. I (and evidently others) doubt it's going to help, but hey, I could be wrong so if you don't mind putting in the effort, have at it.