Stuck batch sparge

[jt]

I thought it was impossible to get a stuck mash with a batch sparge ?

I've had a couple of batch sparges set solid on me lately
Here's how it goes.
Mash then top up, brings mash to 77 - 78C. Wait 10 - 15 min and then recirculate 5 or 6 litres, nice & clear then drain.
Add batch sparge water. Wait 10 - 15 min and then recirculate 5 or 6 litres, nice & clear then drain. But half way through this drain the mash has set solid. Stir, wait and drains ok.

maybe my crush is gettin to fine - but wouldn't this effect the first drain too ?
Does the amount you recirculate contribute ?

Using a perforated false bottom in a round pail

Any thoughts ?

cheers, jt

[James P]

My first stuck sparge was batch, and it was due to a too finer crush, and I was draining too quickly. I reset my gap by eye, reduced my flow and although I have had slow sparges, none have been stuck since.

The other way I read of reducing stuck sparges is to mill on different settings to diversify the milled grain consistency.

[JoKing]

Have you changed your malt recently? I see you are a solid ADM user... so is this the same stuff that is getting stuck - where it wasn't before? It could just be that they have a new batch of malt that crushes differently to the batch you have been sparging with well.

Are you milling your malt yourself? If so, I'd mill off a pound and check the quality of the crush. If there are no "Just cracked" grains - it probably is too fine.

Generally I find with a fine crush, it's when the sparge is less viscous the bed is able to settle in a lot harder. Here's the Science...

When the mash has all the sweet wort in it, the grains within are more "positively boyant" i.e. the sweet wort has an S.G of 1.125, and anything within is more likely to float - so by that theory, the grain bed has lees tendency to fall to the bottom of your tun. When you drin all this heavy wort out, and replace it with water - the grains will be able to sink in and bind together. This is where you need the "just cracked" grains to prop up the grain bed.

I find with my wheat beers that half way through the sparge, the runoff slows down considerably. This could be a similar situation as described above.

Either that.. or your running off too fast!

Tell you what mate... I'm brewing this morning, I'll take a photo of my crush (that never gets stuck) andpost it here for your comparison.

Cheers.

[jt]

I'm on a new sack of it this morning and no problems - but I purposefully recirculated less too so I'll never know.
Judging by your comments my crush is too fine though. I'll go in search of calibration later ...

I didn't think speed of the drain was a problem, thought it was all 'let 'er rip' Jim ?

Boil's started, off to plant some lettuce, cheers chaps

[JoKing]

Definately the speed of the runoff can be the cause of a few headaches. Try the same crush next weekend, and runoff at about .5 Liter per min... that's as fast as I'll go. I try to keep the sparge going for about 45min - 60min.

Photos on their way too...

[jt]

and I was draining too quickly
Try the same crush next weekend, and runoff at about .5 Liter per min
I try to keep the sparge going for about 45min - 60min.

You're talking fly here right ? You reckon I should slow down a batch sparge run off to fly speeds ?

[JoKing]

I dont think it would hurt to try. I realise that there are some fundamental differences between the two methods - but the same principles apply in terms of setting a good grain bed. Have a look at the photo - and if your crush looks anything like it then I'd definately say your running off too fast. If its ANY finer... you get the idea. Search the photo and you'll see more "cracked" grains that I haven't circled.

[jt]

Search the photo and you'll see more "cracked" grains that I haven't circled.

is there a prize for finding them all ?

If its ANY finer... you get the idea.
Hm, I have an idea but those little purple stick figurs are a distraction ..
I might check the mill and maybe back it off a tad
Though having said that, my efficiency's been improving steadily

[MrC]

Could it be that it wasn't actually a stuck sparge?
I sometimes get what appears to be a stuck sparge but is actually an airlock type situation from having the runoff tube immersed in the wort. If I leave it below the surface for too long it stops running. All I have to do is lift the runoff tube out of the wort to let some air in and she starts running again. I've also read about other techniques for letting air into the bottom of the mash/lauter tun to prevent this situation.

[jt]

If I leave it below the surface for too long it stops running. All I have to do is lift the runoff tube out of the wort to let some air in and she starts running again

Yes, I looked at that, thought there may be a pressure problem, but it wasn't, You fly or batch Mr C ?

Realised just after I'd chilled hat i forgot the koppafloc. Looks clear and I'm talking myself into beleiving it's as clear as always .. but somehow I know it just isn't

[MrC]

I used to batch, then I switched to fly. I'm now planning on switching back to batch. I still boil in two pots so batch sparging actually suits my setup better. I was fly sparging just to see what I thought of it when I was doing split wort batches of equal gravity. Now that I have kegs I'll don't see myself doing as many (if any) split batches.

I get the pressure lock sparge problem with both fly and batch. I think it's more a reflection of my setup and technique than the type of sparging.

When I have batch sparged I have always sparged slowly (approx 1L/min) but for my next AG batch (WellyBC APA) I was thinking for recirculating slowly and then letting her rip.