whats your false bottom gap size?

[Junkyard]

We've been having tons of problems lautering big beers. We have adjusted our crush all over the spectrum, we are currently crushing more open than industry standard (measured with sieves) we are beginning to look towards our false bottom. Its a wedge wire false bottom in a 15 bbl single infusion mash tun. we have problems with anything over 1200 lbs of malt generally. our screen gap is .9 mm. I was thinking about increasing this to 1.5 or 2 mm? what are your thoughts?

[dberg]

We've been having tons of problems lautering big beers. We have adjusted our crush all over the spectrum, we are currently crushing more open than industry standard (measured with sieves) we are beginning to look towards our false bottom. Its a wedge wire false bottom in a 15 bbl single infusion mash tun. we have problems with anything over 1200 lbs of malt generally. our screen gap is .9 mm. I was thinking about increasing this to 1.5 or 2 mm? what are your thoughts?

Gap size isn't out of the ordinary. Of more importance is your false bottom loading, ie kgs of grist per square meter.

[dick murton]

That's a bigger gap than most people use. Standard is around 0.7 mm. As already said, gap size is virtually irrelevant for extract performance, but big gaps will simply allow more grain through. The false floor doesn't do the filtering - the grain be itself does that.

That is also a very big tun loading. I would have expected something around 660 to 775 for most beers. If you have that high a loading, then you are probably getting lousy extract figures. Assuming you are aiming somewhere around 5% alcohol, try reducing your grist weight considerably.

[Junkyard]

We are aiming for around 28 plato for these beers. We are operating a 10 bbl brewhouse but opted for a 15 bbl mash tun to reduce the grain loading like you guys are saying. Our efficiencies on big batches like this is low~ 65 percent, but we can live with that as long as we arent taking an extra 3 hours every batch dealing with a stuck mash. Our screens are about 4.5 feet in diameter.

My thought is maybe the flour at the bottom of the tun isnt allowed to flow through the screens and is clogging us up?

[jebzter]

Bigger beers take longer to lauter, the grain bed gets much more compressed.

[BrewinLou]

We load up on rice hulls when going that big on a malt bill. Really helps keep the wort moving.

[Junkyard]

We’ve been using about 25-50 lbs of rice hulls in these batches as well. What would you say is a normal lauter time for a 28 plato beer? 2 hrs right?

On beers around 5-7 percent we’re usually in the 85% efficiency range, but like i said we are totally fine with 65% as long as we can properly lauter the wort.

[BemidjiBrewing]

Hey Dan - it's not a direct solution to your question but you could also consider using some betaglucanase enzyme in your bigger beers to help everything flow easier and potentially increasing the low efficiency you are seeing for your biggest beers. We started using 50 - 100ml per mash of BioBetaglucanse GB from BSG last year to tackle some haze issues (another conversation altogether). However, after chatting with a couple other brewers who use it we have also started occasionally tossing it into our bigger beers to help them lauter a bit easier. We have indeed seen an efficiency bump in these mashes. This could potentially be a way to help stuff flow easier and maybe even reduce the overall load on your screens by removing some malt due to an efficiency bump. I've got a jug or two floating around our cooler, let me know if you want to give it a whirl!

Cheers,
Tom

[Junkyard]

emailed our equipment supplier- our old 3bbl false bottom was 2.5 mm holes, which we didn't have any problems lautering with.

Tom- thanks for the advice on the enzyme we are making an order from BSG today and I'm going to throw some on to try it.

Dan