With equal mash pHs as starting points, the colors of your grains will have a negligible impact on your late runnings pHs. Your mash thickness and target pre-boil gravity are important factors, though. I like using 1 mEq/L as an HLT target because it's low enough to stop chalk precipitation, it's low enough to keep your late runnings pHs reasonable for the vast majority of beers, but it's high enough that having to adjust mash pH upward is rare. The only times I have issues with late runnings pHs are for very low-gravity beers, but you can compensate for that by mashing those beers thin (lower first runnings gravity -> higher late runnings gravity, and the brewhouse efficiency hits are very low for low pre-boil gravities) and - for very low gravities - stopping your sparge early and adding HLT water directly to your kettle to reach your pre-boil volume.
Also, how are you converting dKH to mEq/L? The formula I've used is mEq/L = 0.3574 x dKH, which would result in an untreated alkalinity of 3.43 mEq/L and a treated alkalinity of 0.2 mEq/L in your HLT. To treat 4.42 mEq/L to 0.32 mEq/L instead of treating 3.43 mEq/L to 1 mEq/L, you'll use roughly 73% more lactic acid (assuming the acid is 88 % by wt).
Original Message:
Sent: 06-16-2025 17:49
From: Brendan McGinn
Subject: Lactic acid damaging gaskets/seals and volume level gauge on HLT?
Hi All!
Thanks so much for the help and extra special thanks to Jeff Muston for that first reply! I am not sure how I did it, but I managed to post my question in the forum but not in the email! I am going to try to respond to all the replies here and maybe add another question or two. Apologies in advance if this is a long one! ;)
Jeff,
First off Jeff, I think you hit the nail on the head; high temperatures and also some acid, maybe too much acid. As soon as I read your reply, I remembered that in the first few months after a good sized cellar expansion, an addition of some basic brewhouse automation and an external hxch on our hot liquor tank, there were TWO instances where a brewer who, rather than trusting the HLT/recirculation and heating automation to heat the water for the next day's brew, had manually turned on the steam to the HLT heat exchanger at the end of the brew day. We came back the next morning to rainforest conditions inside the entire brewery and an HLT recirculating boiling hot water. We had condensation everywhere and all the unreachable beams and supports were dripping some sort of converted 5-10year old malt dust goo. It was a colossal mess. It's no wonder I blocked it out! This happened twice before I had special code added to the recirculation function that stops all heating/recirc if the outlet temp of the hxch exceeds 200˚F and fortunately it hasn't happened again! I suspect this is what caused the majority of the damage and it's likely we've been working for the past year oblivious to the fact that the recirculation valve seat had been worn away and was letting water pass by even when the actuator was closed. Several months ago we noticed our flow rate when mashing in and sparging had decreased and we couldn't explain it, but seeing the thin sliver of the recirc piping valve seat made everything make sense!
We had been able to get a year/18 months out of our valve seats when we used phosphoric acid and we made this discovery just doing some annual maintenance.
I read the articles about the PFAS in beer and wasn't exactly sure which microplastics that would be. I've wondered about flex augers in PVC piping for grist and malt conveyance, but I wasn't familiar with Flouro Elastomers and I did not know Viton was one of those. I've only encountered viton in some Thomsen pump seals. After seeing the prices on a set of viton valve seats for the HLT, I think I am going to try some EDPM valve seats again and will monitor the valves over the next 4-6 months and see how things hold up when we don't pump lightly acidified 210˚-215˚ water for 8 hours straight. If certain points in the recirc/hlt piping continue to wear prematurely we can try the Viton out.
Curtis, Understood and thank you. I agree, we'll just have to be diligent and monitor the gaskets and valve seats to stay on top of it. - not sure how we'll get the HLT cleaned up, it's a little too large for hand scrubbing unfortunately! (*thanks Dirk! Maybe the Quat will help!) Maybe we can find a really long telescoping brush... As for that sight glass/level tube, I am thinking that we had some over acidified water in the HLT when it was filled to the top and that more concentrated Lactic acid began to damage the plastic. The tube doesn't get too hot generally speaking, but perhaps some hot water/acid mix did get trapped in there.
Joe, Thanks so much for the response, I was considering that this was likely the case and we've been working on using less Lactic acid in the HLT/CLT and going back to Phosphoric acid in the mashes of most beers, especially the non-lagers but that was mostly out of fear and suspicion that we were getting some (off-)flavor from the lactic in our most pale beers. I remember listening to the MBAA water chemistry podcast years ago and enjoyed it since it sounded like we had somewhat similar water profiles. Our water is pulled from limestone wells. So we have a fair amount of calcium in the water (~60-80ppm Calcium. 30ppm Chloride and 40-50ppm Sulfate) with a fair amount of carbonate. We noticed a number of our beers cleared up a bit when we switched to lactic from Phosphoric, which I credited to the lactic acid not binding to/removing calcium like the phosphoric did. Over the weeks leading up to making my post, I had been thinking about a couple of things, one of which you touched on which was the "laminar" water. We began recirculating our HLT every 10 minutes as a part of the automation upgrades and we soon noticed that the HLT would climb up to 8.3-8.5 overnight and it dawned on me that when we mash in with that water, then top up the HLT with water and then acidify to a target ~5.3, we'd be adding more acid to hit the pH target than was probably needed so I purchased a basic alkalinity test kit... The alkalinity test kit showed that our tap water came in at 9.6dKH or 4.42 mEq/L and our HLT was at 0.571 dKH or 0.32mEq/L at a pH of 5.6 or so. We were brewing a straw/light orange IPA that day with a mash pH of 5.3 and end runnings were 5.6-ish at 4˚P. We've always probably over acidified out of fear of having too high of a sparge pH and last runnings climbing too high, but I think we were focusing on one piece of the puzzle.
I also looked into brewing water chemistry once again and had a hard time finding recommendations for alkalinity targets for different styles. Many of the resources would say don't worry about the pH of the strike water or something like "Your mash pH / flavor ions are what matters, not your alkalinity". Obviously, if the alkalinity was super high it WOULD matter. We add acid to pale mashes and have those additions pretty dialed in over the years. Would you say that your recommendation of 1mEq/L is ok for sparging most beers? Would you target anything different for a porter or stout, or more pale beers?
In any event, thanks to all who replied and sent messages with thoughts. It was greatly appreciated. We'll see if we can 1. Make sure we don't send ridiculously hot water through the HLT valves, 2. Use less acid and extend the life of the valve seats.
Dirk, Thanks for the message. I will get in touch with you. We have some quat left over from our expansion and we had used some in our preparation/passivation of new tanks. We'll see if it is the right chemical and give it a shot.
Thanks again everyone for the help!
Brendan McGinn
Director of Brewing Operations
Zipline Brewing Co.
2100 Magnum Cir Ste 1
Lincoln, NE 68522
www.ziplinebrewing.com
Original Message:
Sent: 6/16/2025 1:27:00 PM
From: Dirk Loeffler
Subject: RE: Lactic acid damaging gaskets/seals and volume level gauge on HLT?
Hi Brendon:
I noticed that everyone missed addressing the black "dust" in your HLT. Most likely this is polishing dust. Dry polishing of stainless steel with nylon abrasive wheels generates an electrostatically charged dust that clings
tenaciously to the polished surface. The dust is pulverized stainless steel and abrasive consisting of either
aluminum oxide or silicon carbide. Because of the strong electrostatic forces involved, the black dust cannot be removed with alkaline or acid detergents. Removal requires neutralization of the electrostatic charge. This is best accomplished using a quaternary ammonium chloride-based product or another cationic agent.
You can contact me directly for a product and the procedure to take care of this common problem.
Cheers,
------------------------------
Dirk Loeffler
Executive Vice President
SEKA Chemicals
(404) 600-1910
loeffler.dirk@sekachemicals.com
Original Message:
Sent: 06-13-2025 14:29
From: Ashton Lewis
Subject: Lactic acid damaging gaskets/seals and volume level gauge on HLT?
Hi Brendan,
Here is an excerpt from a table of elastomer compatibility with a wide range of chemicals. This shows that EPDM is recommended for cold lactic acid, but not hot lactic acid (concentration not provided). Fluoro elastomers, for example Viton, are the best fit of the elastomer types included in this table.
Cheers,
Ashton
------------------------------
Ashton Lewis
Manager of Training and Technical Support
RahrBSG
MBAA District Great Plains, Technical Chair
Springfield, Missouri
(417) 830-2337
Original Message:
Sent: 05-27-2025 18:21
From: Brendan McGinn
Subject: Lactic acid damaging gaskets/seals and volume level gauge on HLT?
Good afternoon all,
Does anyone have any recommendations for the best material for gaskets and valve seats for a hot liquor tank that is acidified with Lactic acid to a pH of 5.0 +/- .3? Usually at a dose around .9-1.25ml per gallon. We are seeing some of our gaskets and other soft EDPM parts deteriorating more quickly since we switched our HLT additions to Lactic acid from Phosphoric acid. It's been nice not having to descale the HLT each month but we have found that the black EDPM seats have been eaten away by the passing liquor as recirculates overnight etc.
- Has anyone else experienced this problem with Lactic Acid in the HLT?
- Is this due to EDPM not holding up to the hot Lactic? or do we need a different "cure" or type of EDPM? Is the grey EPDM better in this situation?
- Should I be looking to source a different material like Viton for this?
Now the other part of this problem, a few months back we were doing some CIPs of the HLT and having recently been through an expansion and had to get new tanks ready for production, our head brewer wiped the inside of the HLT with a white rag after rinsing and noticed some black residue on the inside walls of the tank. How long it's really been there, I have no idea as wiping the insides of 10+ year old tanks hasn't been a regular practice! My first guesses at what it could be were Carbon from our water filters, or rubber from HxCH gaskets and the 1.5" gaskets and valves. We then tried to wash the tank with Citric Acid, PWB, Caustic, Nitric all with no change. The inside of the tank looked clean under a flood light but the white rag test would always show something left on the surface.
Any idea how to remove the surface contamination that won't come off with more aggressive "normal" cip steps?
And lastly, I am guessing this is also due to the acid? We have noticed some discoloring/yellowing of our volume level tube. - Does anyone know anything we can do to prevent this from happening?
Thanks for your help!
Brendan McGinn
Director Of Brewing Operations
Zipline Brewing Co
Lincoln NE