Which is the culprit?

[nigebeer]

Hi, my recent brew, had a problem in that the run off from my boiler slowed right down to zero. This hasn't happened recently and must be due to the ingredients.
Which one of the following is more likely to cause a filter blockage:-

Pale malt
Crystal malt
Wheat malt
I always use whole leaf hops so I presume that they are not the problem.

[boingy]

Are you talking about the run off from the mash tun or the boiler? The reason I ask is you mention grains and hops but they are never together. Grains remain in the mash tun, hops remain in the boiler (unless you are doing a weird mash hop thing...)

[nigebeer]

It was run off from my boiler:-) sorry, and yes it was just the hops, but I don't understand why sometimes It runs right out with no problems and then other times It dwindles into nothing fairly quick.

[Rick_UK]

I've had this problem before and found it was a combination of hop leafs and hot break material.

I now bung the hops in a large voile bag and have removed the hop filter and its been fine since. The hot break material is easily left behind as it floats to the bottom after a few mins anyway.

Rick

[jimp2003]

I have only notice this happen once and it was when I fully opened the tap right at the start of the run-off. The brew started to come out very quickly then ground to a halt before much more than a couple of litres were in the FV.

I assumed that the sudden strong suction had drawn the hops and break material tightly against the hop filter and caused the problem as the ingredients I had used were nothing out of the ordinary. Ever since then I start the run-off slowly and build up to a fully open tap. It might have been a one-off problem however....

[Kev888]

My hop stopper will block if I try to run off before the (whole) hops have settled. The holes in it are small enough that fine break/trub material blocks them, but if theres a bed of hops over the stopper they act like a filter and the hop stopper doesn't see much fine stuff reaching it.

An other thing that blocks it is running off too fast, especially as i pump out - going too fast forces stuff harder against the stopper.

Also, I don't know what type of stopper ypou have, but for info I've found with braid stoppers, if they stretch then the holes in them get smaller. You start out with lots of squarish ones where the spirals cross almost at 90 degrees to each other, and these become diamond shaped if its stretched, and then if it gets stretched further still they end up almost closed.

EDIT: The only problems I've had caused by grain was with a wheat beer that 'also' got stuck trying to run off from the mash tun - lots of stirring ensued, which caused an abnormal amount of fine stuff to end up suspended in the wort going into the boiler.

Cheers
Kev

[nigebeer]

Thanks for the replies,I thought that I had solved the problem, after removing the braided stainless steel sleeve from my slotted copper tubing, the next two brews were perfect, but this last one had the same problem.
I will try running off slowly next time, and maybe a hop bag.

[boingy]

I've found that you don't need really tiny holes/slots for the boiler filter, at least for whole leaf hops which is all I use.
My hop stopper is two 6 inch lengths of 15mm copper pipe, about 2 inches apart, with slots cut halfway through from the underside. Originally I made the slots with a hacksaw but I soon opened them up with an angle grinder so the slots are easily 3mm wide. The whole thing is as close to the tap as possible so I can tip the boiler when it's almost empty to reduce the dead space. I think the small size encourages the hops to form a decent filter bed. I recirculate a couple of litres then fit a fine mesh strainer to the outlet (because I use a plate chiller). 40 odd litres later that mesh filter has stopped half a dozen hop seeds and a couple of leaf fragments so the main filter must be working pretty well.