Water To Grain Calculation ?

[rupal]

What would be the correct or most efficient Litres of water per Kg\grain ratio (including evaporation & grain absorption, etc) for BIAB ? One person says 2.7L\kg, but that doesn't sound right, (2.7L x 9kg\grain =24L)

sorry to start a new thread just for this question but i cant seam to find a clear explanation anywhere & there seems to be nothing in the BiabBooklet.pdf guide about it either.

cheers - Rupa

 

[devo]

I used to do a 2.7ltr to 1gk ratio but now work a 3ltr to 1ltr ratio and prefer the results. That being said efficiency can vary wildly depending on your grain profile from recipe to recipe so I choose not to worry much about it any more.

 

[Adamt]

Depends on your setup as evaporation rate is pretty variable...

For BIAB, you want all the water you need in your pot at the start.. this is:

Your final batch volume + losses due to evaporation in boil (you have to work this out based on your equipment) + 1L water absorbed per kg of grain (a little less if you squeeze?).

 

[rupal]

thanks for the quick response, so what would be a good starting point for my first brew ? I have a standard 50L stock pot & the grain bill for the recipe im doing is about 9kg.

Edit: i should add. 90 min Mash-In @ 65c & 15m Mash-Out @ 75c. And 60 min boil

Edit (again): and it's a 23L batch.

 

[Cocko]

So you are looking at 9L loss to grain on bag removal. Then 15% loss to boil evaporation.

So if you want to end up with say 30 odd litres, which btw 9kg is a shizen load of grain, it would look like this;

45L - 9L [grain loss] = 36L. 36L - 15% = 30.6L.... then a little to kettle / trub loss etc...

You will not fit 45L+9kg of grain in a 50L pot.

My BIAB's go:

35L - 6L grain loss - 15% boil off = 24 odd litres in to fermenter...


All that said, so many variables that you should just start with a basic rule of thumb and work out your own system from there!


I hope it helps!

 

[rupal]

So you are looking at 9L loss to grain on bag removal. Then 15% loss to boil evaporation.

So if you want to end up with say 30 odd litres, which btw 9kg is a shizen load of grain, it would look like this;

45L - 9L [grain loss] = 36L. 36L - 15% = 30.6L.... then a little to kettle / trub loss etc...

You will not fit 45L+9kg of grain in a 50L pot.

My BIAB's go:

35L - 6L grain loss - 15% boil off = 24 odd litres in to fermenter...


All that said, so many variables that you should just start with a basic rule of thumb and work out your own system from there!


I hope it helps!

Thank You Cocko, thats the explanation i was after. Only thing is thats a real bummer about my 50L pot not being big enough, as i have already bought the grain. I might have to use less water & add the rest by sparging or something.

 

[rupal]

Actually to come to think of it, 23L + 15% extra = 26.5L + 7L for grain absorption (with squeezing bag)

Thats 33.5 L of water plus the volume of the actual grain, i think i might just work.

 

[crundle]

You also need to allow for the extra trub generated by BIAB, somewhere in the order of 4 litres overall should cover that.

I lose about 2 litres in the urn after whirlpooling, and about 2 in the fermenter, and I no chill and just pour the whole lot in the cube into the fermenter, so no loss there for my system.

When you say 23 litres, is that into the fermenter, or out of the fermenter at the end?

I am still working out my volumes in BIAB, and have possibly been using less water than I should, which I tend to think has been partly responsible for lower than expected starting gravities of my brews.

You might be surprised to find that you may only lose 0.5 litres/kg to grain if you are able to give the bag a really good squeeze (a good thick set of rubber gloves is a great help in this regard)

My advice would be to get as much water as you are able to into the pot initially, and get some out into a bucket while you are adding the grain so you don't spill any wort, then re-add any you are able to, noting how much volume it worked out to for future reference. With 9kg of grain, your efficiency will work out a bit less than it would with a lower grain bill of around 6kg.

Hope this helps and you have a great brew day,

Crundle

 

[rupal]

When you say 23 litres, is that into the fermenter, or out of the fermenter at the end?

That would be into fermenter....

What's your opinion on using say 10L less water (or however less needed) and once the mash is complete & drained into Cube, i could pour the remaining water (Heated to Mash-Out temp) over the bag of grain then squeeze bag & top-up the cube.

Edit: shit, stupid me. I forgot about the boil. Lol

Edit Again: (I should read what i type before i post it)... After all the drained liquor is in the cube, i would pour it back into the pot & then boil\add hops etc!

 

[apd]

Actually to come to think of it, 23L + 15% extra = 26.5L + 7L for grain absorption (with squeezing bag)

Thats 33.5 L of water plus the volume of the actual grain, i think i might just work.

Assuming the 15% you refer to above is the evaporation, I don't think you can calculate it the way you have. You aren't adding 15% of post-boil volume (15% of 23L = 3.45L), you are losing 15% of pre-boil volume (say, 15% of 30L pre-boil is 4.5L).

What's your opinion on using say 10L less water (or however less needed) and once the mash is complete & drained into Cube, i could pour the remaining water (Heated to Mash-Out temp) over the bag of grain then squeeze bag & top-up the cube.

Yes, you can do this.

My system is a 35L pot into which I put approx 30L water plus 5kg of grist. In a separate, smaller pot I have 6L of water I heat to 70-80*C. After the mash, I raise the bag and do like you say: pour the 6L over/through the bag as a mini sparge. Having said that, it's a pain in the proverbial and I'm not doing that any more.

Now, my question to you is why are you draining to a cube BEFORE you've boiled? If you're doing BIAB, you should be pulling the bag out and boiling straight away. THEN you can drain to a cube or fermenter.

Or have I missed something?

Andrew

 

[rupal]

Assuming the 15% you refer to above is the evaporation, I don't think you can calculate it the way you have. You aren't adding 15% of post-boil volume (15% of 23L = 3.45L), you are losing 15% of pre-boil volume (say, 15% of 30L pre-boil is 4.5L).

So what your saying is i have to add 15% for Pre-Boil and 15% for Post-Boil ? btw 15% is just an example. What's the best way to calculate how much water i will lose from evaporation ? Is there any tool in BeerSmith that will calculate it ?

Now, my question to you is why are you draining to a cube BEFORE you've boiled?

The reason i thought of that is so i can use less water for the Mash (if i my pot is too small) & then sparge the unused water (heated to Mash-out temp) over the mash bag..... Draining into the cube before the boil would just be used as a temporary holding vessel while i sparge, so i don't have to hold the bag above the pot while i pour the water over it... If that makes sense.



cheers - Rupa

 

[mesa]

The reason i thought of that is so i can use less water for the Mash (if i my pot is too small) & then sparge the unused water (heated to Mash-out temp) over the mash bag..... Draining into the cube before the boil would just be used as a temporary holding vessel while i sparge, so i don't have to hold the bag above the pot while i pour the water over it... If that makes sense.

That will work well. Of course now your procedure is suspiciously close to a batch sparge with a bag for a false bottom. If you can get roughtly equal quantities "unused" and "used" water, you'll maximise the amount of sugar you get from your grain. The downside is the amount of extra stuffing around you have to do. If you are going to go this route, and you have an esky of about 40 or 50L you might as well use your kettle as a HLT, the esky as the mash tun and drain into the cube before tranfering back to the kettle so that you end up with a more traditional three vessel batch system.

Have you considered using half your grain to make a half batch? A lot less stuffing around that way.

 

[captaincleanoff]

For BIAB, you want all the water you need in your pot at the start..

I biab, and I mash with 60L, then top up with another 30L after the mash is done. Is this a problem?

 

[rupal]

What i am still not clear about is the amount of extra water to add to compensate for evaporation.... Is there any kind of pattern as to how may milliliters\liters of water is evaporated per minute\hour @ mash temperature (60c-80c) & @ boil temperature ??? And i guess the pot\vessels shape & size would also have to be factored in.


Edit: Did a bit of googling & there are just too many variables to factor in to calculate a precise evaporation rate. It's best for me to do some tests with my own equipment over time. But for my first brew i am still not sure what is a fairly accurate percentage of extra water (Pre-Boil & Post-Boil) to add to compensate for evaporation. :wacko:

 

[apd]

So what your saying is i have to add 15% for Pre-Boil and 15% for Post-Boil ? btw 15% is just an example. What's the best way to calculate how much water i will lose from evaporation ? Is there any tool in BeerSmith that will calculate it ?

Sorry to confuse you. You sound like you've figured it out anyway with your googling, i.e. evaporation is specific to your equipment. You should actually think of evaporation rate as something you should aim for, rather than something that just happens. You should aim for around 10% - 20% and to do that you adjust things like how vigourous your boil is.

The reason i thought of that is so i can use less water for the Mash (if i my pot is too small) & then sparge the unused water (heated to Mash-out temp) over the mash bag..... Draining into the cube before the boil would just be used as a temporary holding vessel while i sparge, so i don't have to hold the bag above the pot while i pour the water over it... If that makes sense.

Gotcha! My trick for this is to get a shelf out of the oven and lay it across the top of the kettle. With the bag resting on the shelf, I pour the sparge water over the bag.

Andrew

 

[marcuspianta]

Sorry to confuse you. You sound like you've figured it out anyway with your googling, i.e. evaporation is specific to your equipment. You should actually think of evaporation rate as something you should aim for, rather than something that just happens. You should aim for around 10% - 20% and to do that you adjust things like how vigourous your boil is.



Gotcha! My trick for this is to get a shelf out of the oven and lay it across the top of the kettle. With the bag resting on the shelf, I pour the sparge water over the bag.

Andrew

similarly, i put one of those stainless steel spaghetti/lettuce strainers under the bag (in the urn/pot) then sparge over this.



minus the lettuce...

 

[katzke]

What i am still not clear about is the amount of extra water to add to compensate for evaporation.... Is there any kind of pattern as to how may milliliters\liters of water is evaporated per minute\hour @ mash temperature (60c-80c) & @ boil temperature ??? And i guess the pot\vessels shape & size would also have to be factored in.


Edit: Did a bit of googling & there are just too many variables to factor in to calculate a precise evaporation rate. It's best for me to do some tests with my own equipment over time. But for my first brew i am still not sure what is a fairly accurate percentage of extra water (Pre-Boil & Post-Boil) to add to compensate for evaporation. :wacko:

Well it is your first brew so dont worry too much. All this talking about litters of kittens has me confused so I can not help with if you can fit it all in your kettle. I brew in about the same sized converted Keg but have never used that much grain (14 pounds is my biggest so far).

My advice is to get some dried malt to adjust the final gravity. You will likely need it for several reasons. First is it is your first BIAB and it is hard to hit gravities in a new system, second you have a bunch of grain and may not get very good conversion, and last you may not get the final volume you want. I have had all those problems until I got used to my setup and still do not hit final volume spot on. Having some dry malt will let you enjoy the process much more while you get your system figured out.

By the way Beersmith stinks for figuring volumes for BIAB. It also stinks for most other setups. I still figure my water by hand calculations. I suggest you follow some of the suggestions until you get your system figured out. Your boil loss will be unique as well as how much you loose in the kettle for hot break. How well you drain the bag will make a difference as well as how many hops you use. Even how you measure your water will make a difference in your final volume.

What you need to do is just brew a batch and see what you get. Get a good starting volume of your water and after each major step. Remember the volume will shrink when it cools by about 4%. I like using a dipstick to measure the volume.

Volume is calculated as final beer + spillage + losses to trub & yeast + shrinkage + what is left in the kettle (including hops) + boil off + grain absorption. Just about every one of those will be unique not only for a brew but also for your system. You can use basic guidelines to get close.

 

[Thirsty Boy]

rupal - the best and most accurate way to calculate what you will lose to evaporation - is to run a test boil. Put nearly 30L in your pot, bring it up to a boil, top it up to exactly 30L (at boiling temps) from your kettle - boil for one hour and re-measure the volume.

Then its not estimating and your figures will be much closer

Testing is always better than guessing

TB

 

[drtomc]

rupal - the best and most accurate way to calculate what you will lose to evaporation - is to run a test boil. Put nearly 30L in your pot, bring it up to a boil, top it up to exactly 30L (at boiling temps) from your kettle - boil for one hour and re-measure the volume.

Then its not estimating and your figures will be much closer

Testing is always better than guessing

TB

I notice that some people (including you IIRC) measure evaporation in L/hr, whereas beersmith has %/hr. The former makes a lot more sense to me. Why use the latter?

T.

 

[rock]

Hi Rupal, I just have done my 2nd BIAB today and I wanted a final volume into the fermenter of 23 Litres.I am using a converted 50 ltr keg and did a black beer and started with 35 Litres, 4.76KG of grain and I had to add 200g of Ldme to up the final gravity to 1049..The end result after a 90 min boil was 22 Litres in the fermenter which was pretty spot on..As other posts have said do a trial run with your own eqipment then u will know the evaporation rate for a 60 min boil..Just have fun doing it and the results will be fantastic.. :beer:
Rod