Stirring mash to avoid stuck sparge

[geobeery]

I'm fairly new to mashing and have suffered 2/3 stuck sparges. My tun is a 23L cool-box with a false-bottom grill. Mashed have been simple 60 minutes at 67°C, properly doughed-in, and I've hit the target temperatures in and out. I've been thinking the sticks were caused by grain by lautering too quickly and/or movement causing the grain bed to collapse. But reading other peoples' experiences has made me wonder about the importance of stirring during the mash, namely because I' haven't been doing that at all.

Some webpages on stuck sparges (here, here, here) make no mention. But it seems to me the grain is probably going to settle quite a lot before it really swells, so there's going to be pressure towards the bottom of the bed where the grain must force the stuff above it upwards as it swells. If this pressure is high enough it seems logical it's going to get compacted, and that if it isn't stirred you're going to have problems.

My next mashes will hopefully be more successful in light of this. But I just thought I'd put this out here as this technique doesn't seem to be covered anywhere in relation to the stuck sparge. Any thoughts appreciated.

 

[CreweBrewer]

I've never stirred during the mash and I only give the sparge a gentle stir after about ten minutes. The only stuck mash I had was because the cuts in my copper pipe filter were too narrow. I've learned that you can be quite liberal with the drill/hacksaw when it comes to making your mash filter without any grain making it's way through.

Dave

 

[clibit]

Stirring is ok if you mash in a bag, but with a mash tun you want the grain bed undisturbed. I have stirred gently when I've had a stuck sparge to get it going again, my tun has a mesh tube filter and I just just gently agitate round the filter.

 

[geobeery]

Thanks both. Interesting. What would you say was the rationale for not stirring? I can't see any reason not to as long as you give the mash enough time (guess ~20 mins) to re-settle before lautering.

 

[markm1878]

When you recirculate before sparging, the first few litres will be cloudy with little bits of grain in. The grain bed compacts and acts as a filter, allowing the wort to flow through (ideally) and filtering out alot of the unwanted proteins and grain debris.

If you stir during the sparge, it'll all go through to the kettle, best avoided if poss. If you then allow it to settle after stirring, you'll need to lauter again and if you're continually doing that, you'll probably lose a few degrees.

If you're getting a stuck sparge, I'd imagine your false bottom isn't up to the job or you're sparging too quickly.

Batch sparging might be easier if you can't change your fb.

 

[Fil]

Or simply batch sparge :whistle:

 

[geobeery]

Hi. I've been recirculating after the mash for 5-10 mins till the wort runs clear of bits, before starting to run off. I'm not talking about stirring at that point - only up to 20 mins or so beforehand to give time to settle. Yes my grill may be a tad on the fine side, although it did work perfectly once so seems borderline. I'm using this stuff - 1.5 mm holes: http://metaloffcuts.co.uk/shop/stainless-steel-perf-sheet.html

Maybe the problem is a combination of that and an over-compacted grain bed..

 

[Fil]

fwiw my ol tun FB had 1mm holes spaced an inch+ appart, and never stuck..
in the new bigger tun im using a similar sheet of SS to yours..

As i batch sparge a damn good stir is part of the process and then a steady drain,

Like you i vourlaff? (jug back) a hell of a lot more than the recommended jug or 2, and feel as if on occasion ive recirculated the full volume more than once..

I think the secret is to keep the valve/tap open durring the jugback/drain, opening and closing can perhaps have an effect on the bed? i crack open for a slow pour for the jugging back and only open up when actually draining and only then a wee bit at a time..

 

[geobeery]

..opening and closing can perhaps have an effect on the bed? i crack open for a slow pour for the jugging back and only open up when actually draining and only then a wee bit at a time..

Hey Fil

Interesting point I'll bear that in mind thanks.

I might give batch sparging a go at some point if this continues to fail. It's encouraging that the hole size isn't the issue.

 

[geobeery]

Just seen - useful reading
http://www.homebrewtalk.com/showthread.php?t=4072

 

[Dads_Ale]

I must say I have found this thread interesting reading as I have never stirred a mash other than at doughing in (don't know why but I just hate that expression :))
I use a 25ltre FV with false bottom and fly sparge using a rotary sparge arm. I only return about 1/4 pint to the mash on first run off.
I have never had a stuck mash in over 30 attempts. (bound too next time now though :lol:)