Strirring mash

[greenxpaddy]

An area of focus for me - improving mash efficiency.

Have realised that I have not been stirring the mash after the 90 mins sit - is this advised?

Fly sparging

If fly sparging do you still top up the mash tun in the same way as batch sparging before carrying on with fly sparging? Do you stir the mash after adding the top up (at raised sparge temp?) ? I believe you need to keep the wort level above the grain bed?

Batch sparging.

Do you stir the mash when adding the top up? How long to leave this for before taking first runnings?

Then after full drain and second top up do you stir again?

Thanks

These seem such simple questions but can't see any definitive answers on this.

[Normski]

Hi GP

I’m sure you will get a few different methods suggested, But I do the following. I fly sparge, I start by running off a couple of liters and returning it gently back in to the mash tun until it looks a bit clearer and bright. I put a tin foil tray with holes in it above the grain. I dont stir. I then start to run off into my boiler. I immediately start to sparge from my HLT in to my mash tun at about 80c or just lower. I keep going until I have collected enough wort. I try to keep a little watter above the grain. I used to try to be very techy about everything, but I now keep it simple and my efficiency is the same at 80%. I know how my kit works and keeping it simple keeps it fun. My brews have never been better.

[HighHops]

I do exactly the same as normski. Run off, then return to tun. Run off and jug hot water on top of tin foil with holes in. Keep the water above the tin foil by a couple of inches. I find my efficiency drops when I get to the bottom of a sack of malt.

[Eric]

This too is but my take on the subject.
You should stir the mash well at the start to avoid any dry spots which will also create an even mash temperature allowing accurate recording.
If you stir after, you will have to allow time for it to settle and recycle for a while. It is normal to stir each batch when you batch sparge.
Stirring can be thought of as moving the grain through the liquid but can't practically be done without disturbing small particles. Recycling achieves a similar result by moving the liquid through the grain and can be done with much less disturbance of the smaller particles.
Normally I won't stir when doing a fly sparge but there has been odd occasion to deal with a problem. There is the matter of balancing input and output flow which will often determine where the water level is in relation to the grain but I aim for the sparge water to be about level with the top of the grain.

[Rubbery]

Hi greenxpaddy,

I batch sparge... Add mash liquor @ 81C wait for liquor to cool to strike temperature @ 73C Add grains and stir Check pH and mash temperature (67C) Mass for 90 mins Raise liquor temp to 85C Top up to first sparge volume and stir Wait five minutes Stir Recirculate first litre then run-off to measuring bucket Top up with remaining sparge liquor @ 85C stirring continuously to stop scorching the mash Fit the hop strainer to the HLT and it is now the boiler Empty the measuring bucket into the boiler using a jug to avoid accidents Wait 5 minutes Stir Recirculate first litre then run-off to measuring bucket Jug the wort from the measuring bucket into the boiler I got 83.5% efficiency for my last brew

[greenxpaddy]

I have been doing as Normski flying with a valentine Arm. No stirring.

Just realised the calculator I have been using for ME is a US calculator

http://www.howtobrew.com/section2/chapter12-5.html

So I have not been entering the right gallon figure - been using UK gallons in it. Thats why I have got it skewed low. 63% originally calculated if corrected actually equates to 75%. Still room for improvement. I think you have a good method there rubbery.

I will stir when adding the top up give it a 10 minute rest before fly sparging. See how I get on

cheers all

[greenxpaddy]

Rubbery I did stir this last brew after top up and I achieved 85% ME. Maybe the water treatment helped also - optimising the ph for max sugar extraction

Seems the way to go in future. Plus maybe doubling the length of braided hose made the draw of sugars more even from across the mash bed.

[gregorach]

I find my efficiency drops when I get to the bottom of a sack of malt.

Aye, this can be a significant factor for home-brew sized batches - we don't get the averaging effect of using several entire sacks of grain at a time. Small samples can vary a fair bit.

[HighHops]

I find my efficiency drops when I get to the bottom of a sack of malt.

Aye, this can be a significant factor for home-brew sized batches - we don't get the averaging effect of using several entire sacks of grain at a time. Small samples can vary a fair bit.

True! It could be that, but I always think it's because it degrades over time though! The bottom of the sack has been hanging around longer than the top which is freshly milled when used.

[spook100]

If your efficiency is dropping when you get towards the bottom of the bag, it may be cause it is not stored in a sufficiently moisture restistant bag. If this is the case, the grain will absorb moisture over time so that when you are weighing it put you are measuring a higher proportion of water than you were at the beginning of the bag and, therefore, less grain. Less in = less out.
Back to the subject of sparging: I do pretty much the same as Normski except that I cut off the sparge water when I am about 10l short of the volume I need and then just let the mash tun drain out as you would when batch sparging. I do this to avoid tannin leaching when the mash pH increases towards the end of the sparge and, hopefully, get all of the dissolved fermentables out of the mash tun. That's just my thinking though; I'd like to know whether others think it makes sense, or is there a flaw in my logic?

[far9410]

i batch sparge in a similar way to rubbery, does anyone think that using a shower head would improve this?

[boingy]

My efficiency seems to actually go up a few percentage points when I get to the bottom of a sack. I've always assumed that it was because there is a higher amount of finely crushed bits and "flour" that have settled to the bottom, which means that there are more "extractibles"in the last bit.

[gregorach]

Depends how you handle your grain... I get mine milled more-or-less as I need it from a local supplier who goes through several sacks a week, so it's always fresh. But even with modern malting techniques, it's not an absolutely 100% consistent product at the sort of small volumes we use.

I've just switched from batch sparging to fly sparging with a rotating arm, so it's a bit early to say if it's made any difference... Calculating my total liquor requirement to deliver my pre-boil volume in the same way though. No top-up, no stirring, just recirculate a little to get the runnings more-or-less clear, then open the tap on the HLT and adjust the run-off from the MLT to keep the mash level approximately constant. Assuming I've calculated my absorption right, just let it run... The limit on my sparge length is the size of my boiler, rather than any worry about tannin extraction.

When I was batch sparging, I'd mash, add first top-up (stirring), let it sit for 10 minutes, recirculate, run off the whole lot, add the second batch (stirring again), let it sit for another 10 minutes. recirculate some more, and run off the rest. Taking temperature, gravity, and pH at each step... (Overkill data-gathering - it's a problem, I'll admit. )

Like I say, it's too early to be able to say anything definite about my results from fly sparging, but for batch sparging I've seen mash efficiencies anywhere from 70% - 85%, depending mainly on the composition and size of grain bill, but also other variables I have not been able to definitively identify - which I'm putting down to variability in the grain. I've tried to repeat batches as accurately as I possibly can (grain bill weighed to within 1g, water treatment to 0.1g, temperatures to within 0.5 degree C - as far as my scales and instruments can tell) and seen a 5% variation in mash efficiency from one batch to the next (from a different bag of grain).