Grainfather mash tun questions - standpipe and mash screen ?

brewman ! said:

Why does a Grainfather have a standpipe in the middle of the mash basket ?

Is the little extender piece that goes on top of the standpipe used on every batch ?

Are there different lengths of standpipes for different volumes of grain and grain/water ratios ?

Why does it have a screen on top of the mash ?

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brewman ! said:

Thanks for the reply.

I don't understand what the standpipe does. Near as I can tell, it either sets the height of the water above the bed to keep it covered at a set height at all times OR it keeps the wort flowing and prevents overflow if the mash gets stuck.

Why are any of these things needed ?

Is the standpipe height adjustable ?

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Kampenken said:

You can operate without the standpipe on small batches but larger ones you need it to hold the top plate in place, which is there to avoid channeling. You could run without both, but why? It does allow for overflow but I'm of the mindset that I want all the wort to recirc thru the grain bed, not go down the pipe and bring loose grains into the boiler. I adjust the flow rate so it doesn't go down this pipe. The GF video does show wort going thru the pipe, I chose a different approach

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shadar said:

Just saw this thread, so I wanted to ask how people manage to keep the wort flowing through their grains so quickly? I've never been able to get mine to drain fully through the grains. The overflow is basically always used unless there's only a tiny tiny trickle of wort being recirculated.

Do you use more or perhaps less water than the grainfather calculators suggest in the mash? Do you use lots of rice hulls?

I could probably get the flow much faster if i used a lot of rice hulls but then my sparge would be insanely fast, rather than the steady pace it is now. If anything I feel like my sparge is a little too fast currently and yet during the mash I feel like the re-circulation through the grains is far too slow. I've given up step mashes because the internal grains never seem to reach temp, at least not for a very long time.

How do you do a 10 minute step when it takes longer than that for the temperature to work its way through the grains?

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Kampenken said:

I will open mine up fully to start and then turn off pump, see how it drains, always runs well. I then turn pump on (after only 1/2 or so of top plate drains off) and adjust valve to pump at ~1/2 rate, maybe a bit slower to start but by 10 min in, its opened up at least 1/2 way and some times close to fully open.

Not sure any of this matters, but here goes. I heat my strike water about +10F and hit my mash temp after doughing in, very thoroughly, and by measuring in the grain bed, ignore controller temp. Only issue is possibly you aren't doughing in thoroughly?

I use maybe a slight bit more, 1L, than calcs. I haven't checked in awhile, but I've done this adjustment just to hit the volume I'm looking to obtain. Of course you need to adjust based on your boil time as well as for high hop usage due to trub losses.

I've only used rice hulls twice, for wheat beers, and the 2nd time was just a handful, worked out well.

Good point on the step, though when I use its really just for a mash out. So, might be heating it 16-20F, and it completes in about 6-8 min or so. Close to time to end the mash, good point, but not exactly what you're experiencing. Wish I had an ah-ha moment there to help, but nothing is coming to mind that's crystal clear. What's odd is that your sparge runs well (mine is mostly done in 20-25 min, how about your time?) and yet your mash does not. My best guess is to make sure you dough in well, and if you do that already, then I'm lost for suggestions.

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shadar said:

My sparge takes less than 20-25 minutes (closer to 10-15) lately because I'm using more and more rice hulls to try and get the wort to drain through the grains faster while mashing. I'm worried it's because of channeling though now.

But I make sure to stir my grains HEAVILY before I put the top plate on. I used to do very little stirring, just enough to get them mixed together without clumps. Now I do almost double that much stirring. Zero change in anything regarding mashing drainage through the grains though. I may try a little extra water.

Also, what alcohol percentage have you been going for? I tend to be in the 7-11% range, so perhaps that is part of it?

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Kampenken said:

Ok, I figured if you'd have these issues you'd dough in well, but had to ask to rule that out.

I don't know how ABV would impact mash. I've topped at about 8.5%, typically in the 5-7.5% range. I presume even at 11% you're not maxing out the grain capacity (though getting close!). Only other issue is possibly too fine of a grain crush, but struggle still to understand the fast sparge / slow mash issue. Do you push the top plate down to the grain bed when you sparge? I have to ask!!

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shadar said:

Just saw this thread, so I wanted to ask how people manage to keep the wort flowing through their grains so quickly? I've never been able to get mine to drain fully through the grains. The overflow is basically always used unless there's only a tiny tiny trickle of wort being recirculated.

Do you use more or perhaps less water than the grainfather calculators suggest in the mash? Do you use lots of rice hulls?

I could probably get the flow much faster if i used a lot of rice hulls but then my sparge would be insanely fast, rather than the steady pace it is now. If anything I feel like my sparge is a little too fast currently and yet during the mash I feel like the re-circulation through the grains is far too slow. I've given up step mashes because the internal grains never seem to reach temp, at least not for a very long time.

How do you do a 10 minute step when it takes longer than that for the temperature to work its way through the grains?

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pocketmon said:

A very good discussion. I should've posted my question about the step mash temperature here instead of the "main" Grainfather thread.

My recently discovery reveals that the recirculation of Grainfather doesn't really mix the wort and mash well. The two screens divide the wort(and mash) into 3 sections: the upper, the middle(mash), and the bottom.

The temperature sensor and heating element are at the bottom, so Grainfather effectively controls the temperature of bottom parts.

Full open of pump valve and letting the wort drain through the overflow pipe will effectively "connect" the upper and the bottom part.

The middle part, the real mash, keeps its temperature and ramps up slowly because the wort goes through the grain bed slowly. If the wort goes through the grain bed quickly, then we will have a quick sparge. This is a dilemma.

The wort recirculation of Braumeister goes from bottom to top. It seems to prevent a compact grain bed. That might be a better way in this case.

PS, I've tried two set of PID parameters. One is tuned with 2 gallons of water while the other is with 4 gallons. I have been wondering why the one tuned with 2 gallons works better. Now I understand.
I used to adjust the pump valve to prevent the wort draining from the overflow pipe. Therefore, I was effectively control the temperature of the bottom parts, which should be a little than 2 gallons.

The picture shows the temperature reading of of bottom sensor(blue line) and upper parts(read line). When I tried to rise 10 deg C, it took over 10 minutes for upper wort to reach the desired temperature.

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Kampenken said:

So a few questions on all of the above, and I did see your post on the main GF thread, but first to be clear on what you're trying to determine. I presume you wish to get to a well controlled mash temp in the grain bed, which is where I, but not all folks, believe the main action is occurring. That being the case, then it is truly reasonable to believe that the GF temp probe is relatively meaningless, other than it is what will turn on/off the heat. So, focus on bed probe only.

Now, ime, I have had a consistent recirc whereby I begin with the valve in ~30-40% open for first part of mash, rising to ~70-90% open after 15 min or so, all done to 100% eliminate any overflow, I wish for all to run through the grain bed- another point of contention where plenty of others have no issue w/overflow. I also hit my grain at dough in w/ ~+10F water temp. After dough in I find I'm at strike temp almost perfectly (I measure the bed temp prior to putting on top plate), while the GF controller will read about +10F! Thus, I ignore. This settles in about 10 min or so, and the heat will come on maybe twice during the mash until its done or I ramp for a mash out.

So, what I'm trying to say above, is that your experience is not surprising. I think wide open valve will have 60-70% of the water recirc without ever going through the bed at least in the beginning using my estimated experience as a guide.

Finally a few things to also consider. One, all temp probes have been calibrated to same measuring points (GF for me was right on with my temp stick). Two, you perform the mash with setting on mash. Three, you strike at a higher temp, will drastically reduce your initial variability as the recirc wort doesn't need to heat up the grain bed so much.

In all of the above, I'm not so sure how much difference to your final beer all this makes. I've read the brulosophy exbeeriments on mash temps and found it interesting, even without scientific replications completed, its still one of the only sources I've read on this, and interesting results.

Good luck!

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