RIMS = Fail

Well actually it's brewer = fail, but I need some help to fix this.

I brewed with my newly built RIMS system today (also my first all-grain experience). Things didn't go well I ended up with a 32% efficiency.

I had 12lbs. of grain and I was circulating roughly 9 gallons of 158* water continuously through the mash tun for about 90 minutes.
I did not stir at all.
I then increased temp up to 168* for a few minutes and continued circulating.
I then transferred the entire volume to the brew kettle and went to work on the boil.

1) Even though the pre-boil was supposed to be roughly 9 gallons was running that much water through mash bad?

2) Should I have slowly worked the temperature up to dough-in? I didn't add grains until the water temp was up to 158*

3) Should I be circulating continuously or should I be taking pauses?

4) Did I do anything right here?

I can't speak to the RIMS part but another piece might be the grain itself. Who milled it, and what did it look like? That can lead to a lot of efficiency problems.

I think the grains were ok. I should have mentioned that in my post, but his was also the first time I crushed grains myself also. They looked good to me but I also brought a 1 lb. sample to my LHBS to confirm, and they agreed the milling looked good.

1) No.
2) No.
3) I would, but efficiency shouldn't be that low even if you don't.
4) Of course.

That's an insanely low efficiency. There are only 3 things I can think of that could be responsible:

First is the crush. You say it's fine, so I'm not going to argue. You'd probably need a lot of uncrushed grain to get that low.

Second is deadspace... if a lot of wort gets trapped elsewhere and doesn't make it to the BK, it's possible... but that'd be a LOT of deadspace.

Third is that you calculated the efficiency incorrectly. This would be the best explanation for almost any circumstances, but especially because this was your first all grain, I'm leaning very heavily towards this one. It would really help us figure it out if you listed your grain bill (and any other fermentables) as well as the post-boil volume and OG.

Edit: Actually, now that I look at it, circulating the entire pre-boil volume is likely (at least part of) the problem - it has a fairly low ceiling for dissolved sugars. You need to have a more realistic water:grain ratio when mashing, too. 1 - 1.5qt/lb works out to between 3 and 4.5 gallons. You sparge with the remaining water.

So you used 36 quarts of water and 12 lbs of grain? Why not a traditional mash and a sparge?

Was the water 158 or was the mash 158? Sounds like you heated the water to 158 and added the grain.

Even if your grain was not crushed, you would likely get better efficiency than that. Are you sure you measured everything correctly?

You should have been mashing with 4-5 gal not 9. Then sparging 4-5 gal after the mash. Also what was the grain bill?

Ok, you guys got me to look back into my math and you are right. I am using BeerSmith and I had a variable wrong. My efficiency now calculates out to just over 60%.

Still too low though. If I had just kept circulating the water for a longer period of time, would that have done the trick?

Grain bill was
11lbs. American 2-row
1 Lb. Munich Malt

Also I was monitoring the water temp in the recirculating kettle, not the temp in the mash tun.

RedBeardBrewer said:

If I had just kept circulating the water for a longer period of time, would that have done the trick?

Click to expand...

No. You should not really have to circulate the water at all after the initial mix. I might suggest working on a simple AG session and then slowly adding in the elements of the RIMS.

RedBeardBrewer said:

Ok, you guys got me to look back into my math and you are right. I am using BeerSmith and I had a variable wrong. My efficiency now calculates out to just over 60%.

Still too low though. If I had just kept circulating the water for a longer period of time, would that have done the trick?

Grain bill was
11lbs. American 2-row
1 Lb. Munich Malt

Click to expand...

Ah, so I was right

But no, longer circulation would not have done the trick. You are mashing wayyyyy too thin. Use a more reasonable water:grain ratio... many here use 1.25qt per pound of grain. Also... let Beersmith do your volume calculations. You need to use more than 9gal of water to get 9gal preboil... the grain absorbs some.

With 3qts/lb and no sparge, you should be getting around 1.043 or so. What was your pre-boil gravity?


http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency

EDIT: Yeah, so assuming you collected about 7 gallons of wort, about 60% efficiency sounds right. If you want to improve your efficiency, you are going to need to thicken the mash and do a sprage. Basically it sounds like you performed a no-sparge.

Also I was monitoring the water temp in the recirculating kettle, not the temp in the mash tun.

Click to expand...

Also, confused by this...what exactly were you setting to 158? If you want to mash at 158, you need the temp of the mash to be at 158, that is you want the grain/water mixture to be 158.

60%-70% is probably about normal for no-sparge. It's the nature of the beast. Adjusting your grain bill to account for the lower efficiency is probably the best you can do without a sparge. Recirculating sweet wort reaches an equilibrium so recirculation time does not increase extraction.

My system is the 10 gallon Igloo cooler mash tun which gravity feeds into a 7 gallon pot on a propane burner. The 7 gallon pot feeds water to a magnetic drive pump which circulates the water from the pot or (HLT) to the top of the mash tun.
I started off by heating 4.5 gallons to 160* and fed it into my empty mash tun to let the heat absorb into the insulation.
While this was happening a heated an additional 4.5 gallons in the now empty HLT.
After about 45 minutes I added the grains to the mash tun which still contained the original 4.5 gals of hot water. I let it sit for a few minutes then cracked the valve allowing the water in the mash tun to feed back into the HLT. At the same time I started the pump up pulling an equal volume of water out of the HLT and feeding it to the top of the mash tun.

I did this for roughly 80 minutes and monitored the temperature of the water in the HLT, which stayed at a consistent 158*. The HLT is where I took all of my temp measurements.

Next I began to increase the temperature my wort (sorry for changing terms) in the HLT to begin to sparge the grains (or at least thats what my goal was). I brought the temp up to 168* and adjusted the valves leaving the pump so 1/2 the flow went to the mash tun and the other half went to a separate brew kettle. After a few minutes I shut off the flow to the mash tun completely and transferred everything over to the brew kettle as the mash tun finished draining.

My pre-boil volume was at least 9 gallons and my SG was 1.032

If I understand correctly, you did basically a no-sparge brew, and that process works, you just have to account for the lower efficiency due to not rinsing the grains. When you drained your MLT runnings back into the HLT, you basically diluted the wort. Then you recirculated this wort with the pump. You did not rinse (sparge) the grains with "fresh" water after your first runnings.

Ok, so I think I see my major problems here thanks to everyone's help

1) I circulated too much water, I should stick to the 1.25 qt./lb

2) I did not do a proper sparge

Adjusting the water volume is obviously not an issue, but how should I go about completing the sparge. Once I transfer say the 4.5 gallons of wort to the brew kettle that I have been circulating, then what?
Do I heat up a fresh batch of water to say 168* and start cycling it through the MLT again?
Do I pump new water into the MLT and let it sit?
Do I pump new water into the MLT and let the cooler drain directly to the brew pot?

The sparge process is obviously where I am stumbling now.

With RIMS you have many options for a non traditional sparge. For myself I have found that I like to add my sparge water at temperature, stir the mash a bit, then recirc for 10 to 15 minutes. After this pump to boil and finish boiling. Over 13 years I have found this to be a good mix of quality, extraction rate, and use of time to keep brew day short.

You could also do many different sparge plans besides what I do. Research here a bit, there are discussions and comments on almost every Conceivable idea from no sparge to very creative and elaborate sparges.

Cheers

I wanted to update this post to report that I have significantly improved my efficiency through some of the techniques recommended. I decreased the size of my crush so it was finer (still no stuck mash issues). I have played with water ratios but when recirculating I have found I need a little extra to keep enough water in the MLT to keep the grains covered and enough water/wort in the HLT to keep the temperature gradual and the pump suction line submerged. I also slowed down the process substantially, I think I was running the system much too aggressively. I have started to sparge as well but I still have a ways to go to do it efficiently. Long story short I can now break 70% which I am happy with for my current make shift brewing system.

Thanks for all the help,
-RBB