Some Advice on the Finer Points of Fly Sparging Please.

[Fat Bastard]

I've been fly sparging for ages with my 36 litre (23l finished) HERMS rig. The normal process has been restricted by my 20l urn HLT, but goes something like this:

Fill urn with X litres of water, add salts and heat to strike temp
Fill MLT (via underlet or through wort return) once strike temp is achieved
Fill urn with Y litres of water, add salts and heat to sparge temp whilst mashing.

X & Y being volumes calculated by Brewmate or (currently) Beersmith.

Despite constant tuning of the grain absorbtion rate, I mostly don't hit my pre boil volume, sometimes missing by 2 or 3 litres either way, but mostly undershooting. I've learned to deal with this by cheating and adding water or DME, but I don't like it and the inconsistancy annoys me.

I'm currently upgrading my rig with a new stand and a massive 80 litre HLT which will be able to provide strike and sparge water, and have another 40 odd available for cleaning.

Can I just continue to sparge until I hit my volume? My plan is to fill up the HLT with enough water to cover me for strike & sparge and 40l for cleaning. I'll treat the whole volume with salts and acid to get to my desired water profile beforehand, as I've managed to get my sparge and mash additions mixed up in the past. I understand that you're meant to stop sparging at 1.010, but I've never actually measured this in my current system so have no idea if I'm near that or not. I suspect I must be over that as I've never tasted any ill effect from oversparging.

I'd appreciate advice from those who know.
Failing that, an argument about fly sparging methods will at least keep me entertained.

Cheers and beers.

FB.

 

[dicko]

Most inaccuracies are caused due to incorrect volume and loss measurements.

First get yourself an accurate measuring jug. Don't rely on the accuracy of a caterers measure, bucket or fermenter markings.

Then make yourself a dipstick for your kettle or Urn.

Measure your mash tun deadspace loss and your grain absorption and Herms loss and add these figures to your software.

From software measure the total water required into your system.

Measure your boil off figure and add that to your software.

Ignore kettle losses until you have managed to balance the water amount from total to wort left in the kettle.

Drain the wort /chill it etc into fermenter and measure what is left.

This is your kettle loss.

Personally I don't worry about kettle loss as long as you are achieving the required volume into the fermenter as these figure vary with hop use etc and tend to skew the the figures.

With a few tweaks in your software you will be getting very closer and very predictable.

Cheers

 

[dicko]

Another thing that warrants mentioning is if you are using a gas burner for the kettle you will need to have a method of setting it the same each time you brew or you will achieve entirely different boil off figures.

A good sparge rate is 1 litre per minute for fly sparging but you can go slower if you want or if you have the time.

Cheers

 

[Gelding]

If I were you I'd continue to sparge until you hit target preboil volume. Such preboil volume needs to be enough to account for losses that inevitably occur during the boiling stage (ie evaporation and hops absorption) and transfer stages (residual loss). Ultimately it should be primarily about hitting post boil gravity (OG)and then your target fermenter volume. If you are getting the OG right but not hitting your fermenter volume, tweak up your grain weight a bit and see how much you collect the next time. Eventually you will have it nicely calibrated. Good luck.

 

[Screwtop]

The correct fly/continuous sparging method is the one which best suits the brew system and provides desired efficiency.

My method.

Filter total water volume (mash and sparge) as calculated by Beersmith into the HLT (90L HLT)

Add acid (lactic) to achieve 6.2PH

Set HLT controller to 76°C and set timer to switch on HLT element at 5am next morning.

Next morning my brewday begins at 6am

HLT has usually reached around 60°C, draw off mash/strike volume to the MLT ** (and 9L to the kettle - more on this later)

Set HEX controller to mash temp and begin recirculating

When the MLT, water, pump and line temp is equalised at mash temp (usually 67°C) the grist is added and given a little stir. Takes about 5 min or so for the mash temp to return to the set value on the controller.

After mash rest (75min) HEX controller is set to 76°C for the mash out ramp.

After 15min the mash and system has reached 76°C and this temp is maintained or the mash out rest of 10 min

Begin runoff (gravity) to the kettle at around 1-2L min

Begin sparge from the HLT (now at 76°C) via pump and HEX (HEX temp still set at 76°C) to the MLT, adjust pump outlet valve to maintain level in the MLT to 50mm above the grist until all sparge water has run out of the HLT. Then drain MLT completely to the kettle.

** Due to high (90% +) mash efficiency sparge water volume has been reduced to provide equal mash and sparge volumes to reduce tannin extraction. This is volume is drained directly to the kettle from the HLT after the mash/strike water has been drained to the MLT. All efficiencies and volumes are maintained. ie: Beersmith calculates a total of 62L of brewing liquor for 7.8kg of grist with 24L (3.5L/Kg) for the mash and 38L for sparge, To result in equal volumes for mash and sparge (24L each) 14L of the 38L of sparge water remaining in the HLT after mash in needs to be drawn off to the kettle to reduce sparge volume remaining in the HLT to 24L.

For my system this results in brewhouse efficiency of 84% and maintains a malty profile in the beer without astringency.

No doubt there will be many more processes described here for you to browse through, it's a matter of what works best for you using your system.

Cheers,

Screwy

EDIT: I moved away from entering deadspace/losses into brewing software some 6 years ago. Find it best to set all to zero and adjust final volume until targets are met. Never use a % for boiloff as this depends upon preboil volume in the kettle. Boiloff should be set as a value or L/pH, this will depend upon the surface area of your kettle, applied and ambient heat and atmospheric losses from air movement over the kettle during the boil. You should have a pretty good idea of how much you normally boil off during your boil in litres. Devide this by the number of minutes you boil for and multiply by 60 for L/pH and enter that as a starting point for boiloff volume.

 

[Fat Bastard]

Thanks. Some points to ponder there.
My system is calibrated to the jug I use to fill, and has been since day one. I've engraved volume markers on the boil kettle for ease, and the jug weighs close enough to 5kg when filled to the 5l mark, certainly not enough out to worry about. I've never measured the losses to the HX, but I had arrived at a figure of 1.3l/kg of grain for losses & absorbtion, which has been mostly pretty close. However sometimes it will sparge to the predicted pre-boil volume, sometimes it will be under, and more rarely, over. This is for the same grain bill, I tend to brew the same beer a few times before deciding it's done and leaving it alone. what normally happens is the sparge runs dry and the pump stops sucking, which I suspect means I'm sparging too fast. I run the pump as slow as it will go and still pump, so it's quite slow. Never measured it, but we'd be in the region of 1-2l per minute for sure.

I get excellent mash efficiency, depending on grain bill as high as 93% for smaller beers. I also have the boil off rates pretty much dialled in (system is all electric) and don't really care about losses to kettle & trub as long as I collect enough finished wort at the correct gravity to fill a 19l keg when it's all said and done.

As it's going to be what is essentially new setup, I guess it's academic at this stage and I'll be needing to do a comissioning brew to see how everything works together. Losses to the system will be large by comparison to the old system as the HLT will be below the MLT, HX and Kettle so sparge will need to be pumped up to the MLT. Space restrictions preclude the use of gravity to do this for me, but I do have 3 pumps that will be electronically controlled so hopefully dialling the speed right back will not be a problem. I have a calibrated sight glass on the HLT, so will be able to monitor levels, but ideally would like to just sparge until I hit my preboil volume and call it done. I think the rest of my process is dialled in pretty well. when I do undershoot the volume, I'm also over in gravity, so adding water to the preboil to make up the missing volume brings the gravity back to within a couple of points of where it should be.

 

[Gelding]

I think the rest of my process is dialled in pretty well. when I do undershoot the volume, I'm also over in gravity, so adding water to the preboil to make up the missing volume brings the gravity back to within a couple of points of where it should be.

In which I case I reckon you have it nailed. Hitting target OG is absolute key. The rest follows.

Addendum: I am not sure why people get so hug up on "measuring" water to hit desired water to grain. For whatever grainbill I charge, I fill the mashtun slowly with water until it stabilises 1 inch or so above the grainbed level. If you are concerned about dry zones, give it a stir with a mashpaddle and let it settle for 15 mins or so and adjust but I find this gets grist/water bang on every time without having to measure water addition.

 

[Yob]

Being precice makes me wet..

And its easier than guessing..

Nothing more satisfying than hitting OG and volume to kettle and volume to cube with leaving stuff all but trub in the kettle. HLT has volume marked so is dead easy..

 

[Gelding]

Being precice makes me wet..

And its easier than guessing..

Nothing more satisfying than hitting OG and volume to kettle and volume to cube with leaving stuff all but trub in the kettle. HLT has volume marked so is dead easy..

What works works

However I don't consider my method as guessing. Though it does save hassle. KISS method everytime.

 

[Fat Bastard]

I think what gelding is getting at is measuring precise water amounts to get an exact mash thickness and sparge amount is bunk.
Which is kind of my theory in all this too. I'll aim to get a 3l/kg mash thickness, because that's what I've found works best with my HERMS, and more importantly, allows me to use less sparge for a desired pre boil volume which is important when your HLT only holds around 16 litres safely when precariously balanced on a milk crate.

So, if I can hit my gravities, there are no obvious problems with continuous sparging until I hit my desired preboil volume, and just shutting off the feed to the kettle regardless of the volume remaining in the MLT?

As an aside, can anyone see any problems with using acidulated and be-salt-ed water for cleaning purposes? Most brews only use 35 odd litres of water and I'll have a HLT that holds double this amount easily.

Cheers!

FB