Decoction - Stuck Sparge - Interesting Day

[korndog]

Well, my buddy and I did a first time triple decoction for a Pilsner yesterday. I use a continuous recirculating mash. After the first decotion, we were stuck.
I used my barley crusher at factory setting. It looks like this was due to crush and compaction and not an equipment issue. We did end up transferring to a cooler and all was good. Loooong day!! Anybody have issues with decoctions and stuck mash?

Note to self: Keep rice hulls on hand.

Here is my fancy rig in action. Notice the precision sparging rig.

 

[bradsul]

I normally have a pretty thick layer of protein on the top of my mash bed when I do decoctions, that could certainly be causing your filter bed to get stuck if you're putting a lot of suction on it with a recirculating pump.

If you use rice hulls make sure to add them just at lautering time, I'm not sure what kind of effect they'd have in the decoction kettle but I'd be worried about strange flavours personally.

 

[Boerderij_Kabouter]

Were you trying to recirculate with the decoction pulled out? Or were you not able to recirc. after the first decoction was complete and added back to the mash? Perhaps, your liquid level was to low and the mash to thick to allow for recirc.

Just an idea, probably not what was happening.

 

[korndog]

I normally have a pretty thick layer of protein on the top of my mash bed when I do decoctions, that could certainly be causing your filter bed to get stuck if you're putting a lot of suction on it with a recirculating pump.

If you use rice hulls make sure to add them just at lautering time, I'm not sure what kind of effect they'd have in the decoction kettle but I'd be worried about strange flavours personally.

Yeah, I guess that makes sense about rice in the decoction kettle. The problem is the stick was after I added back first decoction. I had the pump cranked down to a trickle, but yeah there was amazing protein present. You can see it in the picture too. I vorlaufed with a pump in the cooler after final infusion with no issue. I'm not sure if this was a function of a larger bottom or manifold design, or just that we were thinner at that point. We had 85% efficiency, higher than planned, so I am thinking of backing off the crush for next decoction. I have never had an issue doing normal step mash even with pump going strong. It seems to me that after first pull the mash was pretty gummy and oatmeal like from the procedure.

I have to say, this was a lot of work and a lot of fun; it really helped to have two people there. Doing search for stirring device for decoction kettle.

 

[korndog]

Were you trying to recirculate with the decoction pulled out? Or were you not able to recirc. after the first decoction was complete and added back to the mash? Perhaps, your liquid level was to low and the mash to thick to allow for recirc.

Just an idea, probably not what was happening.

Actually, I think you are right. It was happening after the second pull. We doughed in at 95F, pulled first decoction, infused to 122F, pulled second. While we were at Sacch. rest for second decoction, the recirc. began to fail. We transferred and cleaned false bottom and dip tube. I determined that these were not the cause. We replaced base mash and began recirc. again. The bed stuck again, so we transferred to cooler and infused for sacch. rest without recirculating. Once we added final infusion, we attempted pumped vorlauf with no incident. We ended up fully converted at all steps and had good clear wort. Our gravity was a bit high in the end, but still within guidelines.

 

[BarryBrews]

Well, my buddy and I did a first time triple decoction for a Pilsner yesterday. I use a continuous recirculating mash. After the first decotion, we were stuck.
I used my barley crusher at factory setting. It looks like this was due to crush and compaction and not an equipment issue. We did end up transferring to a cooler and all was good. Loooong day!! Anybody have issues with decoctions and stuck mash?

Note to self: Keep rice hulls on hand.

I know this is an older post, but the following may help someone......

I have fixed the stuck mash problem! It's easy, use a brew bag, use a pump to under let the strike water, then recirculate the wort WITHOUT ever stirring the mash tun. That's right, don't stir the mash! Yep, throw out that mash paddle. And don't worry, brewing is still fun. Under letting really does prevent dough balls. Where as stirring the mash causes the grist to settle out in layers. Think about yeast cleaning in how the fine particles suspend then settle on top, same thing happens in the mash tun. I crush my grist directly into the mash tun alternating bowl fulls of the malts into the mill as a means of mixing, though it's not really necessary. I also use a flowmeter on the output of my pump for consistency and proof that my mash never even slows down. I under let the mash tun at 2 gallons per minute and then immediately start to recirculate the wort at 3 gallons per minute for a 10 gallon batch.

The brew bag is essential for clear wort to the kettle, just as leaving the hops, and the cold and hot break material in the kettle is important for clear wort to the fermenter. I whirlpool my NEIPA hops at 160 F and then let the wort settle in the kettle overnight. I get all the hop flavor without dry hopping and as a nice side effect the fermenter never erupts krausen out the airlock, even with a hefeweizen. The theory being the yeast cling to the solids causing greater movement which leads to faster fermentation and the eruption. My beers have improved dramatically since I started clear wort brewing. It is right up there with oxygen free brewing techniques. Try it.

 

[Vale71]

Where as stirring the mash causes the grist to settle out in layers.

Which is exactly what it's supposed to do BTW. A proper crush with a lot of intact hull material and adequate settling time will guarantee trouble-free recirculation without the need for crutches such as brew bags.

 

[hottpeper13]

I do 5 gal BIAB in my BK and 10 gal MIAB in the cooler tun. Using a bag in the tun is not a crutch but allows me to use the same mill settings ( .025) and get ~80 and 85% eff. Also did a 40% rye malt in a rye wine with no rise hulls, I do believe rice hulls are the crutch.

 

[Vale71]

Using a bag in the tun is not a crutch...

It is if you're not doing BIAB but are using a traditional mash tun with a false bottom which has never required the use of a bag regardless of whether you're recirculating or just sparging.

 

[BarryBrews]

A false bottom is exactly what works the best with a brew bag. Assuming you are using a wort pump and you under let the strike water, the brew bag should not be moved throughout the mash process, nor should you stir the mash. A brew bag guarantees a clear wort to the boil kettle, removes the risk of a stuck mash tun even without rice hulls, and makes cleanup of the waste grist a breeze.

BTW, I ran an experiment with rice hulls from 2 major suppliers, and my LHBS. Using the same mash ratio of rice hulls to 165F water, I discovered that rice hulls make a nasty rice tea from hell! Truly awful taste and smell, not something anyone would want in their beer. I cleaned several pounds with boiling water and then oven dried. Big improvement, but I discovered with MIAB approach rice hulls simply are not needed. Try it.

 

[Holden Caulfield]

I know this is an older post, but the following may help someone......

I have fixed the stuck mash problem! It's easy, use a brew bag, use a pump to under let the strike water, then recirculate the wort WITHOUT ever stirring the mash tun. That's right, don't stir the mash! Yep, throw out that mash paddle. And don't worry, brewing is still fun. Under letting really does prevent dough balls. Where as stirring the mash causes the grist to settle out in layers. Think about yeast cleaning in how the fine particles suspend then settle on top, same thing happens in the mash tun. I crush my grist directly into the mash tun alternating bowl fulls of the malts into the mill as a means of mixing, though it's not really necessary. I also use a flowmeter on the output of my pump for consistency and proof that my mash never even slows down. I under let the mash tun at 2 gallons per minute and then immediately start to recirculate the wort at 3 gallons per minute for a 10 gallon batch.

The brew bag is essential for clear wort to the kettle, just as leaving the hops, and the cold and hot break material in the kettle is important for clear wort to the fermenter. I whirlpool my NEIPA hops at 160 F and then let the wort settle in the kettle overnight. I get all the hop flavor without dry hopping and as a nice side effect the fermenter never erupts krausen out the airlock, even with a hefeweizen. The theory being the yeast cling to the solids causing greater movement which leads to faster fermentation and the eruption. My beers have improved dramatically since I started clear wort brewing. It is right up there with oxygen free brewing techniques. Try it.

This is a very good process if you have the technology to support. If not, then this works for me...

"This often happens to me in my cooler with false bottom mashtun (especially after decoctions). I think what happens is that small particulates settle to the top of the grain bed and slow/stop the wort from flowing, which would explain why it happens after a few gallons are collected.

When this happens, I use my mash paddle (a thin plastic one), turn it so it is like a blade, and make 10-20 scores to the top of the grain bed about a half inch to 1 inch deep. This cuts through the barrier at the top and enables the wort to flow again without disturbing the majority of the grain bed. This usually has to be repeated every gallon or so as the particles resettle into the scores. This trick has saved my day many times with no apparent impact to efficiency or wort clarity."

See this thread for more discussion on stuck sparges and the "Teig" that settles on the top of the grain bed. Per the thread, commercial mashtuns have built in rakes - Stuck sparge, grain in boil, had a BS brew day!