I’ve been a fly-sparger for 15 years and have been using ProMash all of that time. Prior to my move to my electric system, my mashing and sparging water volumes have always worked out well…meaning that the final runoff gravity was just reaching the low limit and I’m running out of sparging water. Now after almost 3 years with my electric system, I’ve come to the conclusion that I probably won’t achieve that coordination again. I always have between 0.5 and 1 gallon of sparging water remaining when the runoff reaches the low limit. By the way, I stop runoff at about 3 brix (1.012) to avoid tannin extraction.
The good news is that my efficiency is very good (80% to 90%). The best I was obtaining with the old system was 82%. The bad news is that my pre-boil volume is too low and the starting gravity is therefore too high. It seems that my procedures are extracting most of the sugars early…leaving the grain bed devoid of sugars. I do use a slightly thin mash ratio of about 1.5 qts/lb, but that is not out of the typical range. I don’t think that is a problem.
It seems that I need to plan on sparging a volume that takes me down to my runoff gravity limit and then take that remaining sparging water and adding it directly to the kettle to meet my pre-boil volume target. I haven’t heard of anyone else doing this, but it seems like it’s what I need to do.
Adding directly to the kettle will dilute what you get out of your specialty grains. It will work, but you may need to tune your process in another aspect to get the results you want.
Maybe, GASP, go with a slightly coarser crush thereby reducing your efficiency by a bit. You’d need to increase your base grains obviously.
Nothing wrong with adding water to the kettle to achieve the correct pre-boil volume and gravity. We Do that on almost every brew. I’m alway wary about over sparging so we cut the runoff b/t 4-5 brix and then top up the kettle w/ the sparge water. You might want to add a lb or two of base to help increase the gravity w/ the first runnings.
I know of a formula to calculate all this ill post it here once I track it out of my files.
Have you tried to go a bit lower on your limit, say 1.008? and see if you notice it. By all means i know i shouldnt ask you especially:) but from my understanding 3 things result in tannin extraction high PH, prolonged sparge durations and high temp. So if PH is 5.2ish, sparge duration kept under 60min and temps are good maybe one may not have to worry as much about tannin/inorganic compounds/Silicic acid Si02? extraction?
I say this because i had the same issue with my EHERMS, seemed to be extracting all the sugars prior to sparge and always ended up short. it was very frustrating so i just sparged anyways to 1.008. No one including myself notice off flavors related to tannin/Husky extraction (pilsners).
I modified my post a bit after i thought about it more:( maybe i am wrong
So i am assuming that yourself/professional keeps the last runnings high, above 1.012? Are your sparge durations long (>60min) ?
Martin, wondering how tight a correlation there is to gravity and tannin/polyphenol extraction. I am more under the impression that pH plays the biggest role. I don’t have Narsiss handy to verify - but I seem to recall that the 1.010 limit was recommended at or near a lautering pH of 6.0 and 75C. There was a lower pH limit, but I don’t recall - seemed well below normal Brewhouse numbers.
Also wonder if you are seeing a slight drift in your base malt modification. I noticed some inconsistency in yield from bag to bag from a local maltster and confirmed with a congress mash. Something about that batch converted inconsistently and made it into the bag. Three years of the trend would likely rule that out though.
Perhaps a more coarse? I crush between 0.04 and 0.045 and mash at 1.5 qt / lb to keep my RIMS moving as fast as possible.
On my homebrew system my sparge is maybe 30-40 min on a 5 gallon batch. But I try not to run off too fast. I take refract reading every gallon then very few Qts when I get to about 6 brix.
Matt, I found that there is some sort of threshold below which tannins were extracted into my brews. I had been using 2 brix as the cutoff for about a half dozen brews and kept finding a very mild tannic astringency in those beers. Moving the cutoff gravity to 3 brix solved that problem, but my problem was that I was too focused on kettle volume and the fact that I still had a bunch of water in the HLT.
I use RO water with alkalinity of nearly zero alkalinity and it would only take a drop or two of acid to drop its pH well below 6. I don’t runoff for super long periods. I’m usually done with the runoff in about 45 minutes. That is similar to the time I was taking before this issue presented itself, but I did switch from my LHBS’ crappy milling to milling my own grist with a MM-2.2 that is set at 0.035" gap. It is a very fine crush, but my pre-conditioning of the malt prior to the crush is leaving a large percentage of intact husk for filtering. My RIMS flow is still pretty good.
The fact that 90% of my sugars do make it into the kettle is encouraging. It’s just that I had not run into an inability to run the entire calculated sparging volume through the grist before. I had less volume of wort, but at higher gravity. Now I will conduct operations more like Black Sands and monitor the runoff gravity more closely and just end runoff as the refractometer indicates and add any remaining water in the HLT directly to the kettle to meet my pre-boil volume goal. That should avoid the potential for tannin extraction.
Thanks for the guidance on this issue. I figured that this was a solution, but I’d never heard of anyone doing it that way.
On Friday a Vienna was brewed, most things went well and I cut the sparge at 3 Brix. Tasted the runnings and those had tannins! I acidify my RO sparge water to 5.5 (about 2 drops of phosphoric), temperature was not too high. I recently bought a new refractometer, not sure how accurate it is as I have not calibrated it. The new refractometer measured 1 Brix!
I think this is why I have had some low level tannins going on for a long time, the gravity was lower than indicated on the last runnings.
What to do? Make a solution of water and sugar, do a serial dilution and plot the curves for the 2 refractometers and the hydrometer, indicated Brix/SG vs actual. I might have to break down and get a finishing hydrometer for the lower Brix readings.
Jeff, you raise an ominous specter. Now I’m going to have to do some cross-checking on my refractometer too. As mentioned, this may be more reason to end the runoff earlier.
Once you calibrate the refract and know its reading correctly. I also test it against my hydrometer at the proper temp and they are usually spot on. Good luck!
Have you done a serial dilution of a known Brix to make sure it is linear at low Brix? The old one had been dropped and abused several times, but last I checked was fine at 15 Brix. Didn’t take it down to 1 to 4 Brix.
Some will say putting water on and setting to zero is calibrating. That is zeroing, but what about slope and linearity?
Have you done a serial dilution of a known Brix to make sure it is linear at low Brix? The old one had been dropped and abused several times, but last I checked was fine at 15 Brix. Didn’t take it down to 1 to 4 Brix.
Some will say putting water on and setting to zero is calibrating. That is zeroing, but what about slope and linearity?
You did point out a little astringency on my German Pilsner that got a Bronze at the 2011 NHC. It was noticed when I sat down and read the scoring. I have been chasing it for a long time, maybe now I have a clue!
Look, I know this is kinda a radical suggestion, but why not try batch sparging to possibly \alleviate those problems? At least to me, it seems so obvious.
