Daft question about sparging

[The-Engineer-That-Brews]

I brew with a 3V setup, and recirculate continuously during the mash.
When it comes time to sparge, I do what I believe is a ‘fly’ sparge: I turn off the pump and allow the liquor to drain slowly into a collector, while feeding in hot acidulated sparge water at about the same rate. Thus I adjust the flow so as to keep the liquor level about the same as during the mash itself; and I continue collecting until either I’ve got the required volume or the runnings hit 1010 SG (normally both things happen at about the same time).
I assume I’m not going too far wrong, because I normally end up with the correct gravity for the recipe. However, I’m almost always left with a mash tun full of liquor, albeit very watery; and I’m wondering if this is right - I’m thinking maybe I should be stopping adding new sparge water a bit earlier, so that I’ve pretty much drained the grain bed down at the end of the process.
What’s the general approach on this please?

 

[Ossiary]

Hi TETB, do you use any resources like Beersmith or Brewfather? My process is exactly like yours but I set the brew day up in Beersmith and use the water volumes from that. Need to set up the equipment profile with dead space etc. to reflect your kit, but I’ve found it really reliable once that’s done. I end up with a dry Mash Tun and almost always the target volume in the Kettle.

 

[BeerCat]

In your situation I collect the wort leftover from mashing, let it settle, decant and boil it to feed my collection of bugs and yeast. I normally end up with 2 or 3 litres. I don't fly spare though I refill the master with water, recirculate for 10m then drain again. My mashtun won't drain fully as I use a bag as well.

 

[user 18729]

Beersmith etc should tell you exactly how much strike and sparge water you need. I fully drain my MT and then following beersmith’s calculations I’m within 1 litre or so of my desired pre boil volume
If you use brewnwater then those volumes of mash and sparge liquor are important (the mash liquor volume far more so than the sparge)

 

[The-Engineer-That-Brews]

thanks @Ossiary @BeerCat @Hopsteep
So there seems to be a consensus that i should be draining the mash tun down fully - great, that’s really useful.

Interesting though, because I suppose the risk is that once a part of the grain bed is uncovered you are no longer washing the sugars off those grains, unless there’s some sparge water running past.

Maybe the answer is to drain all the ‘standing’ wort out of the mash first, and then start fly sparging…?

 

[The-Engineer-That-Brews]

In your situation I collect the wort leftover from mashing, let it settle, decant and boil it to feed my collection of bugs and yeast. I normally end up with 2 or 3 litres. I don't fly spare though I refill the master with water, recirculate for 10m then drain again. My mashtun won't drain fully as I use a bag as well.

Really interesting - that sounds a bit like the old fashioned way, where they made different grades of beer from the ‘first‘ and ‘second’ runnings :-)

 

[Ossiary]

I understand that the technique of sparging at the same rate as you lauter keeping the liquid level the same is believed to help ensure thorough rinsing of the sugars from the malt. To drain and then refill is fine (Batch Sparging), but draining and then fly sparging might result in channelling of water through the path of least resistance leaving a lot of sugar in the mash.

 

[The-Engineer-That-Brews]

Beersmith etc should tell you exactly how much strike and sparge water you need. I fully drain my MT and then following beersmith’s calculations I’m within 1 litre or so of my desired pre boil volume
If you use brewnwater then those volumes of mash and sparge liquor are important (the mash liquor volume far more so than the sparge)

Yep I have beersmith, but I only got it recently so I’m still learning its ‘little ways’ LoL…

 

[Ossiary]

I know what you mean! Measuring out dead space etc really helped me dial in the volume and temperatures of water to use.

 

[The-Engineer-That-Brews]

draining and then fly sparging might result in channelling of water through the path of least resistance leaving a lot of sugar in the mash.

very good point! Ah yes…. Hmmm…. do you fly sparge at full rate (I.e. the same rate as the runoff) until all the calculated volume of sparge water is used up, and then stop (while still collecting wort); or do you taper off the inflow so it ends ‘smoothly’ ??

 

[Ossiary]

In my Limited experience I match the lauter rate until the calculated sparge water volume has been added and then basically let the MT drain at the same rate. I’m only 6 All Grain brews in, so take this with a pinch of salt until more experienced members chip in?

 

[Ossiary]

The flow rate is pretty low, so 30 min plus to fully sparge and drain

 

[The-Engineer-That-Brews]

I know what you mean! Measuring out dead space etc really helped me dial in the volume and temperatures of water to use.

Yep I measured the dead space under my mash screen recently, for that reason, and I was a bit shocked how much it was: it’s only an inch and a half, but it adds up to 3L!

a great suggestion (I forget who) was to go to Lidl and buy a load of cheap LDPE chopping boards, cut them to size and use them to fill the dead space

 

[The-Engineer-That-Brews]

I’m only 6 All Grain brews in, so take this with a pinch of salt until more experienced members chip in?

heh I’m about the same number of brews but spaced over 12mths :-)
I don’t think you should be adding salt to the mash tho

 

[Ossiary]

That’s a great idea!!! My dead space is about 5L so that could make quite a difference. I can feel an experiment coming on....

 

[JohnB]

Hi Engineer, I have a similar system to yours by the sounds of things. 3V system, 60Lt boiler/mash with 1/2 inch ball valve, using gas burner. 50Lt Sparge vessel with false bottom and 1/2 inch ball valve, and 50Lt collector. I work out my mash liquor volume to give a mash thickness anywhere from 2.0 to 3.5 Lts/Kg, I know how much liquor the grist will hold (absorbency c1.2Lts/Kg), I then calculate how much extra liquor will be required to get me to my expected boil volume, add on the dead-space (4lts in my case). Usually I am just running out of sparge liquor by the time I get down to 1.012SG and by the time the sparge vessel is empty I am at boil volume with final runnings at 1.010. Hope this helps and gives you some ideas to work on. J.

 

[The-Engineer-That-Brews]

Hi Engineer, I have a similar system to yours by the sounds of things. 3V system, 60Lt boiler/mash with 1/2 inch ball valve, using gas burner. 50Lt Sparge vessel with false bottom and 1/2 inch ball valve, and 50Lt collector. I work out my mash liquor volume to give a mash thickness anywhere from 2.0 to 3.5 Lts/Kg, I know how much liquor the grist will hold (absorbency c1.2Lts/Kg), I then calculate how much extra liquor will be required to get me to my expected boil volume, add on the dead-space (4lts in my case). Usually I am just running out of sparge liquor by the time I get down to 1.012SG and by the time the sparge vessel is empty I am at boil volume with final runnings at 1.010. Hope this helps and gives you some ideas to work on. J.

Yes - brilliant mate; that's ideal and really helpful.
The 1.2 litres per kg absorbency is a useful figure - that is the amount of liquor that the grain 'hangs on' to and doesn't run out?

 

[Buffers brewery]

My brewing water calculation has evolved over the time that I’ve been brewing (not very long) and is totally empirical. I now now that if I get 6.5 gallons of wort I’ll get a little over 5 gallons after the boil into the FV. To get 6.5 gallons of wort I start with 8 gallons of water, 3 gallons for first mash then 2.5 gallons for subsequent mashes and a squeeze of the grain at the end. I started with 7 gallons of water and came up short at the end so gradually increased until I got the volume I wanted at the end. I haven’t found that the grain bill makes a significant difference in the outcome.

 

[BeerCat]

Really interesting - that sounds a bit like the old fashioned way, where they made different grades of beer from the ‘first‘ and ‘second’ runnings :-)

Yes its called parti gyle.

 

[JohnB]

I've always been interested in parti gyle brewing, Ron Pattinson has lots to say on the subject and I believe it was the main system used by Fullers in London. I have been told that our local brewery (Bateman's) also does this with its XB and XXXB brews. Makes sense really.

@engineer - yes, mate. without squeezing the malt, or hops (I use leaf hops as a filter for the wort) I lose about 1.2Lts of liquor per Kg of grain bill. Just been looking at one of my brews and the numbers are as follows, I included hop losses which are small but they are there:
Grain bill: 5.0 Kg
Mash thickness 2.5 (Lts/Kg)
Mash Vol 12.5 Lts
First runnings 6.5 Lts
Sparge volume 25 Lts
Boil Vol 32.5 Lts
Hop losses 0.26Lts
Dead Space 3.0 Lts
Malt Loss 6 Lts
Boil-off 4 Lts
Fermenter Vol 24.5 Lts.