New Brew Rig And Low Efficiency

[cdbrown]

I originally thought everything went reasonably well for the first brew on the 3v herms rig apart from taking a bit longer, HLT heated nicely, the HERMS kept the temp right and after the boil ended up with the perfect amount in the cube. Last night poured it into the fermenter to find an OG of 1.034 which is a fair bit lower than the 1.050 I had aimed at. Did another 2 brews that weekend including a double batch following pretty much the same procedure so now fairly concerned they will be about 50% efficiency (or lower) into the fermenter.

4.9kg wey pils malt, milled using a mashmaster mill with the notch at the top, powered by a drill - had to have the revs high or it would get stuck. Added grain to tun and pumped 13L of 75C water into the tun through the mash return. Gave it a stir to get rid of any doh balls and then started recirc the mash through the herms. 64c for 90mins, ramp to 75C over 10mins, hold for 10mins before draining to kettle. Pumped 26L 75c water to the tun and then recirc that for about 10min with herms maintaining 75c. Drained to kettle and boiled for 90mins.

Just wondering what could the key factors be that caused the low efficiency - milling speed too high causing flour, tunneling of liquor through mash bed, if the PID was out by a few degrees would that reduce the conversion to fermentable sugars? Speed of recirc, should the herms pid be set to a slightly higher temp than desired to ensure the mash is at the right temp?

Any advice would be much appreciated as I'm keen to do another brew this week.

Cheers
-cdbrown

 

[gap]

Did you take any gravity reading through your brew
process , ie first runnings, gravity in kettle pre boil, gravity post boil???

 

[razz]

Just a couple of things on your second last paragraph cd.
Extra flour from milling may cause your mash to set, but you would soon see this when recircing. I condition the malt 30 mins before milling and get no flour.
Tunneling of liquor through the mash may occur and you may see a gray sludge on top of the mash and you need to get rid of this to stop channeling.
If the temp was out you would get a more/less fermentable wort but the OG should be the same. I have my PID thermo at the out put of the herms and set it for what ever the rest temp needs to be.
You really need to take readings before and after the kettle to make sure you are on track for your recipe, this will also help to dial in your numbers in Beersmith etc.
Overall I think the low efficiency is most likely sparging or perhaps your calibrations may be off, volumes etc.

 

[beerbrewer76543]

What was your final volume? 4.9kg of grains should be good for 1.050 at around 23 litres...

edit: did you over sparge?

Cheers

 

[cdbrown]

I took pre-boil, but that reported the grav was higher than the target based on temp conversion so don't have any confidence in that amount. I didn't take first runnings grav. Grav post boil is 1.034. My measuring of gravity during the process was pretty much non-existant as I was focused more on checking flow and PID temps. Next brew will put the hydrometer into the kettle as I fill along with a thermomemter.

With the recirc I had the tun outlet and valve to herms fully open, but over time it would slow to a trickle. I'm not to sure what the flow rate should be. So temp of mash doesn't affect the OG of the wort? Did I sparge correctly - once I added the sparge water I just began recirculating for 10mins. When draining I had all the valves open fully and it drained completely.

Final vol was about 23L - 1L left in kettle, 21L into cube.

 

[beerbrewer76543]

Maybe you could do two sparging steps to better wash out the sugars from the grain...

I'm interested to hear how it goes so I can avoid making the same mistakes when I [eventually] get my HERMS rig running

Cheers

 

[Online Brewing Supplies]

Tunneling of liquor through the mash may occur and you may see a gray sludge on top of the mash and you need to get rid of this to stop channeling.

Tunnelling may be a problem but Razz you are not correct about the sludge on the top of the grain bed , this exactly where it should be. This aids in the filtering or the wort, it is protein and you dont want this in your kettle.
Back to CD's problem :

Could be a stuck mash, very likely if you are new to the system.

Where there any obvious cracks in the grain bed or around the edges (pulled away) ?

Did you check for conversion with Iodine ?

Did you check your pH ?

I bang on about these last two because with out these factors being correct you cant answer the problem without it being speculation.
GB

 

[razz]

GB my reference to the sludge was about it causing the liqour to channel around/over it. I never said that it should go into the kettle. For mine, ever since I've used a herms the sludge does not form on the mash, it used to way back when......... :mellow:

 

[Screwtop]

GB my reference to the sludge was about it causing the liqour to channel around/over it. I never said that it should go into the kettle. For mine, ever since I've used a herms the sludge does not form on the mash, it used to way back when......... :mellow:

And dare I say....................................... +1

Did you check for conversion with Iodine ?

64c for 90mins,

Did you check your pH ?

Don't know if this would be much of an issue, imagine his PH would be roughly the same as pre HERMS batches.

Last night poured it into the fermenter to find an OG of 1.034 which is a fair bit lower than the 1.050 I had aimed at.

I took pre-boil, but that reported the grav was higher than the target based on temp conversion

Wondering why his postboil is low when the preboil was high ??????????????

Screwy

 

[cdbrown]

Nev - I didn't notice any cracks or gaps in the bed, but to be honest I wasn't really looking for it. The other two checks you mentioned I've never heard of so that would be a big no. Do you sell the gear to do those tests and when should those tests happen?

I don't recall any sludge being on top.

 

[white.grant]

. Added grain to tun and pumped 13L of 75C water into the tun through the mash return. Gave it a stir to get rid of any doh balls and then started recirc the mash through the herms. 64c for 90mins, ramp to 75C over 10mins, hold for 10mins before draining to kettle. Pumped 26L 75c water to the tun and then recirc that for about 10min with herms maintaining 75c. Drained to kettle and boiled for 90mins.


Cheers
-cdbrown

I'll preface this by saying I don't use a Herms but I am herms curious. On my simple system I mash out at 75C I don't mash in at that temp. Won't adding 75c water to the grist prior to mashing switch off a whole heap of enzymes and reduce your yield? Or are Herms different?


cheers

grant

 

[manticle]

Not with you Grant. If I add strike water to grain (or vice versa) I usually go 9-10 degrees above mash temp. 75 sounds reasonable (water temp not mash temp).

 

[cdbrown]

Meant to say 71c not 75c. Was following beersmith instructions which give the higher temp to cover temp loss of system and grains. Once recirc began through herms the PID was reporting the temp to be about 62c. But I lack confidence in that number.

 

[Screwtop]

Meant to say 71c not 75c. Was following beersmith instructions which give the higher temp to cover temp loss of system and grains. Once recirc began through herms the PID was reporting the temp to be about 62c. But I lack confidence in that number.

Don't stress re numbers, that is "your" temp, if the beer lacks mouthfeel raise "your" temp.

I much prefer to add water to the tun and wait for 5 min for temp stabilisation before adding grist. Temp is generally about 3 or 4 degrees above mash temp when I add my grist.

Screwy

 

[white.grant]

Not with you Grant. If I add strike water to grain (or vice versa) I usually go 9-10 degrees above mash temp. 75 sounds reasonable (water temp not mash temp).

My mistake I was thinking that 75 was the stable temp.

cheers

grant

 

[Online Brewing Supplies]

GB my reference to the sludge was about it causing the liqour to channel around/over it. I never said that it should go into the kettle. For mine, ever since I've used a herms the sludge does not form on the mash, it used to way back when......... :mellow:

Sorry CD for the side tracking but this no sludge has got me interested .Where does the protein sludge go ? It must form some where in the mash ? I dont know Herms but would imagine its the same as normal traditional brewing, protein forming wise? I always have a nice bed of sludge on top of my lauter , its just meant to be there. I have seen it working commercially and at home brewing level. It indicates to me that you have recirculated well before run off. Have I missed some thing here?
GB

 

[kevin_smevin]

what kind of efficiencies were you getting in your old system. what are you using to take gravity readings? Have you used your mill before or is it new? Lots of questions. Dont really have any idea if its something to do with your system except some problem with you sparging. What liquor:grist for you mash?

 

[Banshee]

I'm assuming you have your temp probe at the exit of your heat exchange. I'ld try a coarser grind so less flour and also stir the mash every now and then to stop any channeling. I think you can only trouble shoot by doing one maybe two things different next time so you can see the results thosr changes made.
Change to many things you won't be able to pin point what gave you better results.
So myself, I would coarse grind and stir see if rersults differ.

 

[cdbrown]

Like I said I don't recall seeing any sludge, wasn't looking for it and didn't know there should be sludge - so perhaps there was.

Old system was an esky lined with swiss voile - getting around 70% with that. Have used the mill before, but this time it was mounted to a frame, need to add an adjustable feed from the hopper so I can slow the drill down a bit. I've been speaking on PM with someone and draining speed seems to be an issue - I just used the pump to suck the tun dry and most likely way too fast. Ran the system with the valves fully open to get good flow, but I guess good flow is bad results.

13L for 4.9kg grain - from beersmith.

 

[mintsauce]

yup - I was also under the impression that slow flows were good (if I run too fast I get a stuck sparge) - takes me ~30 minutes to fly spare a 40l batch....not sure if this is too slow (and not sure my efficiences are that on, I always have to add water at end to make back up to batch size then the OG is right about where beersmith puts me with 75% eff)