[BrewBama]

...but you have given me an idea. I could use a one gal stainless steel milk can to gravity drain the MLT after the mash is complete thereby eliminating the problems Keith pointed out in reply #8 above. I can use a hose from the MLT valve to fill from the bottom of the milk can. Then manually transfer the sweet wort (gently — without splashing) to the BK ~one gal at a time.

By happenstance that is precisely what I do (draining a gallon of wort gently into a 6.5 gallon bucket with a hose running to the bottom of the bucket then swapping in a second bucket and repeating over and over until the full transfer is complete and the batch sparge water is added, stirred, and the same process is repeated).

Cheers!

+1 It tends to solve the problem doesn’t it.

[Thirsty_Monk]

Some people do not like wort grant. The argument is that it oxidize the wort.

I do use wort grant but wort intake is close to the bottom of the grant. Wort out is in the same level as intake. This way if you have any grain under the screen it will collect on the bottom of the grant.

Lautering is a fine balance of grain crush and lauter speed. These are two easy controlled variables. Another variable that is much harder to change is lauter tun design.

Shallower tun = faster lauter but if it is too shallow, sparge water will not have enough time to to rinse the sugar out.

If you want to be more scientific you can look up screen load formula. Not sure if you want to go down that rabbit hole

[BrewBama]

Some people do not like wort grant. The argument is that it oxidize the wort.

That’s my concern with a grant.

I just stumbled upon another possibility for my lower than expected efficiency that I thought may have been attributed to recirculation speed.

In the Blichmann BrewEasy system instructions they recommend an orifice placed between the MLT valve and drain line to control runoff speed via gravity.  They also recommend ’raking’ the top 1/3 of the mash bed every 15 minutes during the mash without disturbing the bottom 2/3 of the mash bed. Both of these steps are used to ensure channeling is not occurring in the recirculated mash.  That seems to corroborate my recirculation concern. Channeling during recirculation was my concern all along.

I don’t have a BrewEasy but the principle that I am using  is the same: recirculated infusion mash.  While they use an orifice, I am using a flow control valve and rotameter to measure and control recirculation.

The mash bed shouldn’t care if gravity is pulling on the liquid, siphon is pulling on the liquid, or a pump is pulling on the liquid if the flow is restricted with an orifice or a valve.

I do not rake my bed but it’s easy enough to do so I may try it.

Another issue that may be occurring is mash bed temp. This addresses Denny’s conversion efficiency question. I have been relying on the RIMS PID display to monitor temp. I will use an actual mash bed temp measurement next brew. I may find I have been mashing at a different temp than the display tells me. I may have to increase or decrease the PID SV to maintain an actual mash bed temp.

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[Thirsty_Monk]

I never gave it a thought the you would not hit the desired mash temp.

[BrewBama]

I never gave it a thought the you would not hit the desired mash temp.

I don’t know. I’ve always trusted the PID PV display.  ...but I’m going to find out next brewday.

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[goose]

Just to add one more comment here.  I have always fly sparged and usually run off the wort at the rate of one gallon every 5 minutes.  That's my sweet spot.  Any faster than that and my efficiency goes down (at least on my system).  I also knife the top inch or two (depending on the batch size) of the mash several times during the run off to allow the sparge liquor to more efficiently rinse out the sugars from the grain bed.  I set my recipes for 80% and usually hit that with my lighter beers.  The heavier ones with a biger grain bill usually come in around 75%