First Full AG tomorrow - move from BIAB - mash/sparge volumes

Tomorrow I plan on christening my newly built mash tun. For the last year I've BIAB'd and had some excellent beers.

I'm a bit unsure on the volumes of water to sparge with. I'll be aiming for 20l in the FV and will be using 4.65kg of grain. Aiming for a mash temperature of about 68 degrees. I'll be batch sparging.

According to the calculator on Jim's Beer Kit site I'll need the following.

Going to heat water to 75 degrees in HLT
Mash with 11.6 litres of liquor
Heat strike water to 85 degrees
First batch - 8.7l of liquor
Second batch - 13.6l of liquor

This should give me about 25l pre-boil taking into account dead space etc. I reckon I'll lose as much as 2l to dead space but still playing about with the mash tun.

The question I guess is why the different volumes for the 2 batches? Why not just add 11l to each batch?

Other than that does the above look OK?

Cheers, Ian

The reason for different volumes are that you will get the best efficiency when the volumes collected from the 2 batches are the same, in this case two batches of 13.6L

So you will add 11.6L to the mash then add another 8.7L before you collect the first volume. That is 20.3L in total but you will lose approx 4.7L due to absorption of the grain, and another 2L due to dead space. That means you will only collect 13.6L from the first batch.

You will then add another 13.6L of sparge water for the second batch. This time you don't need to factor in absorption or dead space (because they are already full) so you will collect another volume of 13.6L.

That gives a total preboil volume of 27.2L. Hopefully that makes sense.

strange-steve said:

The reason for different volumes are that you will get the best efficiency when the volumes collected from the 2 batches are the same

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This is interesting. Any idea why this would be the case?

IainM said:

This is interesting. Any idea why this would be the case?

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Absolutely no idea :?
However more clever people than I have apparently done research into it. Quote from BYO:

It is relatively simple to figure out how much water to add for each batch. Most of the following is drawn from and builds on the work of Ken Schwartz and Bob Regent. The main concept to understand is that, for the best efficiency, the runoff volumes from your mash and batch sparge should be equal. In order to do that, it’s sometimes necessary to infuse your mash with extra water before the first runoff.

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So I wouldn't drain the mash tun of wort when the mash finished? Instead I'd add the 8.7L, stir and then wait 15/20 minutes and then run the wort off. Once drained I'd then add another 13.6L, stir, wait 15/20 mins and the run off again?

ian_r said:

So I wouldn't drain the mash tun of wort when the mash finished? Instead I'd add the 8.7L, stir and then wait 15/20 minutes and then run the wort off. Once drained I'd then add another 13.6L, stir, wait 15/20 mins and the run off again?

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Exactly :thumb:

Many thanks. Fingers crossed for tomorrow.

Since it's your first time with the mash tun, have a few spare litres of sparge water ready in case your volumes are a bit under, but don't stress too much, after you've done it once you'll see how simple it is. What are you brewing?

Could someone educate me please? It seems to me that you should mash with as much liquor as your mash tun will hold (grains + liquor) then sparge to top up to required pre boil volume. That's what seems logical to me (and what I do when biab) but not what I believe most of you do. Is there something else going on perhaps chemically that makes a less diluted mash beneficial?

Yeah, this is why I asked. I was under the impression that thinner mashes were suppose to be more efficient due to less product inhibition.

ian_r said:

Tomorrow I plan on christening my newly built mash tun. For the last year I've BIAB'd and had some excellent beers.

I'm a bit unsure on the volumes of water to sparge with. I'll be aiming for 20l in the FV and will be using 4.65kg of grain. Aiming for a mash temperature of about 68 degrees. I'll be batch sparging.

According to the calculator on Jim's Beer Kit site I'll need the following.

Going to heat water to 75 degrees in HLT
Mash with 11.6 litres of liquor
Heat strike water to 85 degrees
First batch - 8.7l of liquor
Second batch - 13.6l of liquor

This should give me about 25l pre-boil taking into account dead space etc. I reckon I'll lose as much as 2l to dead space but still playing about with the mash tun.

The question I guess is why the different volumes for the 2 batches? Why not just add 11l to each batch?

Other than that does the above look OK?

Cheers, Ian

Click to expand...

I learned to calculate my recipes by hand using these two resources:

http://www.howtobrew.com/
http://homebrewmanual.com/home-brewing-calculations/

I think it really gave a good foundation to start all grain with. I've actually built all of the calcs that Iearned into an Excel spreadsheet that calculates everything for me now. Water volumes, IBUs, strike water temps, colour, required grain quantities, pre boil gravity etc.

Anyway, long story short, if you haven't already, have a go at learning how to calculate recipes by hand. It will be well worth your while. It will also give you a much deeper appreciation for the entire process.

and of course the fine folks of this forum are always willing to help too

strange-steve said:

Since it's your first time with the mash tun, have a few spare litres of sparge water ready in case your volumes are a bit under, but don't stress too much, after you've done it once you'll see how simple it is. What are you brewing?

Click to expand...

Going to do a pale ale hopped with Nelson Salvin. Probably use 100% Maris Otter but may chuck a handful of torrified wheat in. Yeast will be a sachet of S33 unless my geterbrewed order arrives in which case I'll use S-05.

Thanks for all the replies. It's as much a test for the mash tun as it is for me.

Got my BIAB volumes spot on after the first couple of brews so sure that this will come together pretty quickly.

IainM said:

Yeah, this is why I asked. I was under the impression that thinner mashes were suppose to be more efficient due to less product inhibition.

Click to expand...

You're absolutely right a thinner mash will be more efficient, however the more water you put in the mash the less you have for the sparge, which will lower the efficiency slightly, so I suppose it's a balancing act to get the best of both worlds.

The "default" mash thickness seems to be around 2.5L/kg which is why a top up is often needed at the end of the mash. But to be honest I don't know where that ratio comes from and I always add the top up water at the beginning of the mash for the sake of simplicity.

In practice, I have a feeling that the mash thickness has very little impact on the finished beer.

If you fancy a read there is some great info on mash thickness amongst other things here.
http://www.braukaiser.com/wiki/inde...ciency_in_single_infusion_mashing&redirect=no

but for the mash thickness its summed up in the conclusion thus.
The thickness of the mash doesn't seem to effect the fermentability of the wort that is produced but thinner mashes can significantly improve the conversion efficiency. As a result brewers who see low efficiency from their mashing may try to use a thinner mash (3-4 l/kg or 1.5 - 2 qt/lb) as they were shown to convert more starches.

OK, brew complete but with somewhat mixed results.

The brew used 4.65Kg of Maris Otter and aiming for a batch size of 20L.

The mash tun was great. Held the mash temperature fine and no issues with draining through my stainless tubing manifold/bazooka. This was made from a length of tubing from the Crazy Wire Company (Here). Drained nicely.

I'm not sure that my dead space calculation was accurate though. When tested in water I was left with 2.4L but got more wort than expected from the first run off. I'm thinking that the weight of the grain helps to pin the tubing to the base of the mash tun whereas in water it tended to float about a bit. The end is weighted down with a piece of copper pipe.

Started as per the plan in this post.

Mash with 12.5L of water. Was aiming to mash at 68 degrees but this ended up being around the 65/66 degrees mark. The temperature held fine for the hour so the additional insulation added to the tun was worthwhile.

Added 8.5L of top up water. Temperature was around 72 degrees after this was added and stirred. Left for 15 mins and then drained. I was expecting around 13.6L but ended up with 15.5L which is why I think my dead space calculation is incorrect.

Added a further 12L of water as I was aiming for 27L pre-boil. After stirring this was around 75 degrees. Left for 15 minutes again the drained. What I noticed with the second batch was straight away it was a lot lighter in colour than the first batch. Almost to the point of looking like water towards the end of the drain. I did taste a sample about half way through the drain and it still tasted sweet. This had me worrying about the efficiency I was going to get. A hydrometer reading led me to expect an OG of around 1.042 taking into account the temperature of the wort. I was aiming for around 1.052.

Anyway, the 12L ran through as expected leaving me 27L to boil.

After boiling and cooling I ended up with 20L in the FV which was the target batch size.

OG was 1.044.

So, pleased with the mash tun - just need to try to figure out why I ended u[p with 2L more than expected in the first batch. Pleased with the water calculations but disappointed with the efficiency. Was hoping for around 65% to 70% but ended up with 59% which is worse than all my BIAB attempts.

Used a sachet of US-05 and hopped with magnum and nelson sauvin so will still have a beer around 4.5%.

Any ideas then why the second batch was much lighter than the first (assume to do with sugars and most coming out in the first batch)?

And anything obvious I have done wrong here as I was expecting more from this beer?

The grain was bought pre-crushed at the back end of last year from a local brewery and lives in the garage. I weigh out the amount I need the night before and it is moved into the house. I did a BIAB brew the other week and got 65% efficiency.

Cheers, Ian