An unusual question, just to stir your brains

[Meaulnes]

There is one question that has been bothering me for a long time.
Which grain absorption should we use in order to calculate water volumes: apparent or actual?

First let me precise what I mean by apparent absorption et actual absorption.
Almost all beer software use the grain absorption in the following way.

(a) Mash water + Sparge water - Grain absorption = preboil volume

(here we suppose all is considered cold meaning volume quasi equal mass)
In fact this is only appearance, because the preboil volume is not all water but contains sugar (extract).
Similarly, weighing the grain before mash and weighing spent grain and then calculating the difference doesn't give the real water absorbed because the grain has lost sugar.

Lets take an example

Grain mass: 5 kg
Grain yield: 80 %
Mash efficiency: 75 %
Mash water 17 liters
Preboil volume (cold): 24 liters i.e. preboil volume hot 24 * 1.04 = 24.96 liters

With these data we can calculate the sparge water
according to (a)

Sparge water =Preboil volume -Mash Water + Grain absorption
Sparge water = 24 - 17 + (0.8 * 5)= 11 liters
Sugar (extract) in préboil volume= 5 kg * 0.8 * 0.75 = 3 kg

Knowing the volume 24 liters and the sugar mass 3 kg and using a convergent iterative algorithm we can obtain the gravity and the water mass
In this case:

gravity 11.927 platos (SG 1.0481) and water mass 22.15 kg (or liters)

Thus the actual absorbtion is

Mash water + Sparge water - Water mass in the preboil volume
17 + 11 - 22.15 = 5.85 liters
Actual absorption is 5.85 /5 = 1.17 l/kg.

Now let's assume that we are using the actual absorption to show how the calculation works

The extract produced is the same i.e. 3 kg
We the preboil volume and the sugar mass using the same algorithm we can get
the water mass in preboil volume, still 22.15 liters

And we can calculate sparge water using the actual absorption

Sparge water = Water in the preboil volume - Mash water + Grain absorption
Sparge water = 22.15 - 17 + (1.17 * 5) = 11 liters

This seems perfect but there is a rub. You probably has noticed that passing from apparent to actual varies a little bit depending on the mash efficiency and grain yield.

The question is: what is more independent from these 2 factors : apparent or actual absorption ?
Assuredly using the apparent absorption is a bit easier because it doesn't require the use of the iterative convergent algorithm.

 

[Clarence]

It's a very interesting question in theory, but how much does it matter? Most of my beers use a similar amount of malt and in any case have to fit in the mash tun. I tend to use the same water to grain ratio regardless. I allow space to be able to adjust the temperature with boiling water. At sparging time, I sparge until I have collected the required pre-boil volume, which, for me is designed to boil down to a little less than the required batch volume since I like to top up (liquor back) to the target OG even if the volume is sightly out. In short, I always hit target OG even if the batch volume is a little short or long. Another advantage of brewing slightly short is that I can liquor back with near freezing water, if required, allowing me to reach pitching temperature more readily.
My question to you is: will knowing the actual or apparent absorption of the grain allow me to brew better beer?

 

[Clint]

I use the same amount for mash and the same amount for sparge (roughly) for every brew. I "measure" using the Litre marks on my big jug. The 4 Litre isn't quite 4 Litre,I weighed it full of water! As I've done this quite a few times my volumes are spot on...or there abouts! Any shortages on the sparge,it's usual within a Litre I use extra out the kettle and any excess I stop sparging as I know where my boil kettle needs to be. Differences to fv can be a slight boil off variance in the summer or more left behind with a larger hop bill.

 

[Meaulnes]

It's a very interesting question in theory, but how much does it matter? Most of my beers use a similar amount of malt and in any case have to fit in the mash tun. I tend to use the same water to grain ratio regardless. I allow space to be able to adjust the temperature with boiling water. At sparging time, I sparge until I have collected the required pre-boil volume, which, for me is designed to boil down to a little less than the required batch volume since I like to top up (liquor back) to the target OG even if the volume is sightly out. In short, I always hit target OG even if the batch volume is a little short or long. Another advantage of brewing slightly short is that I can liquor back with near freezing water, if required, allowing me to reach pitching temperature more readily.
My question to you is: will knowing the actual or apparent absorption of the grain allow me to brew better beer?

You are fundamentally right. My question is theoretically interesting but practically lacking interest. Using sophisticated software leads us to forget common sense. Your answer doesn't lack cleverness and relevance. What is important is the goal we aim at? For you it's target OG no matter the batch volume misses its target and it's probably the same for most of us.
And moreover the difference between the 2 approaches is probably so tiny that it doesn't matter at all provided we use which of the 2 values the software expects: that is to say the two must not be confused.

 

[Bzee]

the difference between dry and wet grain weight would give you the amount of water absorbed

 

[Meaulnes]

the difference between dry and wet grain weight would give you the amount of water absorbed

Not the actual value as grain has lost sugar. It will be apparent value.

 

[MashBag]

I like to think I have some common sense too, but it might be experience.

I brew with no sparge, no software and would top up the FV if I missed the mark.

 

[Meaulnes]

I like to think I have some common sense too, but it might be experience.

I brew with no sparge, no software and would top up the FV if I missed the mark.

I should give a try to this way of doing things. But isn't that a waste of grain? At what value do you estimate the loss of efficiency?

 

[MashBag]

Oh no no no no.. Not efficiency too.
I don't know what mine is. Never have.
But I do know my beer tastes smashing (others opinion)
I also know that the difference between 75% efficiency & 83% (say) sounds fantastic but in reality is very very few grains at the volumes we make.

You will waste far more grain when you make 40 bottles of subverting recommended, only to find it "hangs about a bit"

We have a brewing setup all to ourselves. We can do with it what we want. No shareholders no accountant no customers other than ourselves. We can make wonderful free-range beer.

Answer me this... So why do sooo many people copy blindly what the 'Big boys' do, buying expensive miniaturisations of the brewing vessels and beiveing the maths over their taste buds and in the next sentence call there product commercial ****?

II am only here for the beer

 

[Clarence]

Answer me this... So why do sooo many people copy blindly what the 'Big boys' do, buying expensive miniaturisations of the brewing vessels and beiveing the maths over their taste buds and in the next sentence call there product commercial ****?

It's a fair comment, @MashBag , and I'm inclined to agree with you up to a point, but there is also a fair answer and it lies in the motive for brewing in the first place. If it's a given that we all want to make good beer then what else? I like to use basic and cheap equipment because that's the way I started, a penniless student with an unquenchable thirst, and wanting to get the best beer and the best value for as little outlay as possible. My technique still reflects this and I do sparge and I don't waste litres of beer on a whirlpool. From reading others' contributions on this forum I would say that eg @DocAnna is a perfectionist who wants to perfect the process, the equipment and the packaging of her favourite styles to exceed the quality of commercial products and cost is no object. Then we have @The-Engineer-That-Brews whose motives are given away by his name. Others just love to have the shiny stainless steel, as much as possible, they maintain it with the love and care that others give to classic car or it's building up a miniature of a commercial brewery with pumps and control software that floats their boat. Others, sadly no longer with us, are at least as interested in exploring how different yeasts work and how they can be stored or how the overall chemistry, incuding water chemistry affects the beer @strange-steve and so on. So if @Meaulnes finds the theoretical maths a stimulating byproduct of producing great beer, then all power to his elbow. Looking at your posts, I'd put you down as partisan du moindre effort as they say at Asahi Headquarters. And why not? Effort requires energy which we're all supposed to be conserving!

 

[Meaulnes]

It's a fair comment, @MashBag , and I'm inclined to agree with you up to a point, but there is also a fair answer and it lies in the motive for brewing in the first place. If it's a given that we a want to make good beer then what else? I like to use basic and cheap equipment because that's the way I started, a penniless student with an unquenchable thirst, and wanting to get the best beer and the best value for as little outlay as possible. My technique still reflects this and I do sparge and I don't waste litres of beer on a whirlpool. From reading others' contributions on this forum I would say that eg @DocAnna is a perfectionist who wants to perfect the process, the equipment and the packaging of her favourite styles to exceed the quality of commercial products and cost is no object. Then we have @The-Engineer-That-Brews whose motives are given away by his name. Others just love to have the shiny stainless steel, as much as possible, they maintain it with the love and care that others give to classic car or it's building up a miniature of a commercial brewery with pumps and control software that floats their boat. Others, sadly no longer with us, are at least as interested in exploring how different yeasts work and how they can be stored or how the overall chemistry, incuding water chemistry affects the beer @strange-steve and so on. So if @Meaulnes finds the theoretical maths a stimulating byproduct of producing great beer, then all power to his elbow. Looking at your posts, I'd put you down as partisan du moindre effort as they say at Asahi Headquarters. And why not? Effort requires energy which we're all supposed to be conserving!

@MashBag, @Clarence Your discussion is of great interest to me. It forces me to put myself a little (even totally) in question. When I started brewing some five years ago I decided without really thinking very long, to opt for an all in one equipment. I never used a classic (multiple vessels ) equipment,in consequence of what I have trouble clearly distinguishing what is really the best.
This said, entering a new universe (like the homebrewing universe) one needs time to find his way. It enough to just stumble upon a pro-software site to get caught up in a certain way of thinking.
Nevertheless, many times, I have wondered about the relevance of accurate calculations from highly uncertain ingredient data finding that more often than not the target is missed and that in the end, things are recoverable relatively easily.
I also find MashBag's approach quite relevant and I thank him for shaking up unspoken conventions.

 

[DocAnna]

I've come to this thread following the tagged comments by @Clarence - which by the way I will take as a compliment (Though I'd dispute the cost part - but you had a point). To return to the OP, the answer to how much water is enough. Volumes and masses will depend on so many variables about the grain and environmental conditions that precision about sugars extracted and volumes can never be calculated from theory exactly. In a commercial setting practice will vary with the scale too, I suspect the high volume international breweries will measure the moisture content of each grain batch, but many won't. At a home brew scale, the amount of liquid used to sparge with is the amount to bring your preboil volume to a particular target, be it a set preboil volume, a particular preboil gravity, or an amount because the software tells you that's the amount to use. In the case of software, it will likely be round about where you want it to be. If you brewed the same recipe several times you might dial it in a bit differently to reach one of the other targets.

At a full commercial scale it's all about mass balance - any mass entering a system has to leave it somehow. Commercially, it may be better to sacrifice the most efficiency possible to ensure consistency between batches, whereas with homebrew we are usually reaching for the best we can possibly do. As for @MashBag I'm sure you make excellent beers, by experience, practice and the definition of artistry.... it is what you enjoy and you like. For some of us, we do like to consider the science behind what we do, it doesn't make things necessarily better, maybe just a bit more complicated.

Some of us like complicated .


(Oh and I like shiny stainless steel kit too.... but can't cope with the high mass cost of steel to low productive volume ratio for home brewing )

 

[The-Engineer-That-Brews]

Then we have @The-Engineer-That-Brews whose motives are given away by his name.

Guilty as charged, m'lud!

Mind you as well as getting at least as much pleasure from designing and making the brewing kit and associated electronics as I do from the actual brewing, I also like to know what's actually going on in my mashing and fermenting processes (especially temperature). I'm with @Hazelwood Brewery on this : it's very hard to get a repeatable process if you don't have reliable data.

 

[MashBag]

Looking at your posts, I'd put you down as partisan du moindre effort as they say at Asahi Headquarters. And why not? Effort requires energy which we're all supposed to be conserving!

Guilty.

... And perhaps a smidge more. I hate waste, in any form. It is not just effort

"partisan du moindre" does translate (I had to Google to check) "less is more"

And in contradiction I own a Braumeister

 

[MashBag]

@Meaulnes
I think we started brewing in the same place. Brilliant thread.

 

[MashBag]

As for @MashBag I'm sure you make excellent beers, by experience, practice and the definition of artistry.... it is what you enjoy and you like. For some of us, we do like to consider the science behind what we do, it doesn't make things necessarily better, maybe just a bit more complicated.

Some of us like complicated .

If I think about that it sounds like a gentle slap, that's fine and I might have got that wrong.

I agree with you, some of us like complicated, professionally & personally I do too. Then I distill it down the research. Some subjects distill well, some not so, some distill into... nah "not worth it"

As Clarence brilliantly put it, we are all motivated differently. We all see different things and do different things.

Me.. I am off to find hot dog recipe in the library to share.... Keep it it up Doc, They've gotta learn

 

[Rodcx500z]

I have been brewing all grain for about 4 years what have i learned, 1 my beer is generally good
2 i use brewfather very loosely, if it calls 19.3L of mash water i will go with 20L or 9.6L sparge i go 10
3 i check pre boil volume if it is under i leave it and do the boil at a simmer as aposed to a full on boil on full power, if at the end of the boil if it is under i just except what i have, if i am over what i aimed for i crank to full power to get the required amount,
4 i would say that puts me in the keep it simple bracket, i have just started to use yeast for the style my last brew a kolsch i used K-97

 

[DocAnna]

If I think about that it sounds like a gentle slap, that's fine and I might have got that wrong.

Oh gosh I didn't mean that at all, it was if anything trying to be self deprecating on my part. I do not ever put people down*, personally or professionally, it's never worth it.

[EDIT* I make an exception for some politicians]

 

[MashBag]

Anna, absolutely no worries. Like I said it's often how you read it.

Ps. Can't find a decent hotdog recipe will chilli cheese recipe do

 

[Bzee]

I disagree with comment above about needing data for consistency.
I touch, smell and often taste my ingredients, saucepan and tun. I rarely use scales and never use a hydrometer any more. I've made my version of an American pale over 100 times now, the results are pretty consistent.