Ugh... tinny, sharp, tart, slimy wort after SSBT kettle upgrade

[goodolarchie]

I need your help folks. TL;DR is I need to make sure my new SS Brewtech BME kettle isn't contributing terrible tinny off flavors to my wort. I've tried BKF, PBW, Oxi-clean, StarSan... I'm still getting this effect.

Now for the long version!
About 2 months ago I upgraded to a 20 (really 22) gallon SS Brewtech BME kettle from a 10 gallon. It was my birthday present a couple months ago. I have brewed on it twice and both times, the wort came out with a distinctly slimy, metallic character. I can only describe the lingering mouthfeel like that you'd feel if you ate 3-4 tums and didn't drink water.

When I got the kettle, I did a hot water filled PBW soak (not cheap!) and recirculated with the whirlpool port for about an hour, then I did a rinse, and star-san soak, followed by another rinse. I did that on the morning I got the kettle because I was excited to brew a 10 gallon batch.

On brewday, I had a great single infusion mash, the hot scotchy was tasty. However I noticed after heating up my strike water in the BME that there was some "pitting" of the kettle at the bottom. This was the first time I had put heat to it, there was lots of water in the kettle (15 gallons), and I set the flame low to break it in. It looked like small dimples that would probably clean up / come out. Keep in mind, this was just from heating up strike water with a little gypsum / calcium chloride in it, nothing else in the kettle yet, it's the same water chem I do in my 10 gallon kettle. I gave it a scrub and rinse during the mash, the pitting didn't really come out. Well, time to boil, so RDWHAHB. A couple photos:

After racking for fermentation, I noticed that rainbow swirl that tells me the stainless steel might need to be passivated. More on that later.

The next day, I pull a sample of the beer (sample port on conical). I can only describe this as a flavor I hope to never taste again in my life. It was a tinny, ridiculously astringent tartness. If you ever used an old TV that had a "tint" setting, it was like a TV that had been set to all green tint, but in your mouth. Yuck. At first I thought it was a hop-burn like effect, but it's now almost 2 months later and I have a pint of the ~11IBU hefe I brewed (brew #1), I still sense that tinny flavor and slimy mouthfeel. It's not from hops, it's not from tannins or a poor mash, poor pH, etc.

I was so frustrated by this that I went back to the 10 gallon and did a small batch of a dry irish stout. It turned out fantastic, like revenge-brew great, I might enter it into a competition. Same mash, same variables, other than the kettle, malt bill, hops and volume.

So yesterday I worked up the nerve (and the need) to do another large batch of base lambic, and again my 65% pils 35% unmalted wheat mash went well, tasted right, color pH and pre-boil gravity were good. However the resultant wort was like dirty dishwater, with that same tinny metalic burn, and a bit of slimyness. I've never had my lambic turn out like that. I pitched a few cultures into the wort and will try it tomorrow, but the results I got yesterday were very disheartening, and I really think it's the kettle.

The dishworter:

What steps should I take to make sure that the kettle is not the culprit? How should I clean / passivate the SS? Any next troubleshooting steps are greatly appreciated.

 

[V-Fib]

I don't think the small pitting marks would be the cause but I would contact SS to see what they recommend since it is new and should be under warranty. I would look at the valve and see if its packed with grease.

 

[Hermit]

Given the stuff that comes from China today I'd be worried that it wasn't the grade of stainless you paid for. I've abused my cheap stainless and never had pitting or discoloration like that.

 

[goodolarchie]

I don't think the small pitting marks would be the cause but I would contact SS to see what they recommend since it is new and should be under warranty. I would look at the valve and see if its packed with grease.

Which valve? It's three welded tri-clamp fit ports. So the only valves are the ones I've attached, and those are ones I've used before. I will reach out to SSBT though, that's a good idea. I was hoping there was some uncommon wisdom I could tap into to try here before I go to them (I suspect they'll say we'll exchange your kettle since the pitting was a defect, but I wanted to make sure that was necessary...)

Also it's my understanding that some of the brewtech guys lurk this forum.

 

[Carlscan26]

Have you tried washing it with dish soap and warm water? Scrub out every port really well too.

 

[Vale71]

It could very well be residue from machine polishing of the internal welds. If that's the case than you need to thoroughly polish the internal surface of the pot followed by a passivation regimen. But since the kettle is new and cost a few $$ I'd contact SSB first.

P.S. One sure way to know if you have iron in your beer is to wet your skin with it (the back of the hand is a good spot). Iron will react with the coating of your skin and the smell will be increased 100-fold.

 

[czmkid]

Here’s how to clean it for first time use straight from the Ss site. Having three of their unitanks I can tell you that if you skipped the TSP soak step that the machine oil is your issue. There was a ton of it on all the tanks especially in the ports. If you did not passivated then that’s why you have the spots on the bottom....

STAINLESS STEEL PREP
• (3) TC Clamps • (3) TC Gaskets • (2) TC Caps


Pre-Clean: Prior to first time use, thoroughly wash all surfaces of the Ss Brew Kettle BME, including all valves and fittings, with Tri-Sodium Phosphate (TSP) in hot water, mixed to the manufacturer’s rec- ommendations. Scrub with a soft terry cloth, and after the initial TSP wash, rinse thoroughly and dry all surfaces.


Passivation: It’s good practice to periodically passivate all stainless steel equipment with an acid based solution to establish a uniform passive oxide layer that will maximize corrosion resistance.

Following the pre-clean step, fill the Ss Brew Kettle BME with Star San at a concentration of 1 ounce per gallon at 70- 80°F for 30 minutes.


Moving forward, for best stainless performance, passivation should be performed at least once a year or anytime you believe you may have inadvertently scratched the surface.



***Save this Star San solution to perform the pressure testing step covered later in this guide.


Cleaning and Sanitizing: As part of a regular cleaning regimen, both pre and post-fermentation, wash the interior surfaces of your Ss Brew Kettle BME with an alkali cleaner such as PBW at a ratio of 0.75 ounce per gallon. Then sanitize with Star San or another acid based sanitizer per the manufacturer’s recommendations.

 

[Vale71]

If he didn't passivate then one batch is not going to ruin the kettle, it is stainless steel after all. Most homebrewers don't even bother with it. Having residual welding material all over the surface will however cause corrosion in no time and simple passivation will not effectively remove it.

 

[goodolarchie]

Here’s how to clean it for first time use straight from the Ss site. Having three of their unitanks I can tell you that if you skipped the TSP soak step that the machine oil is your issue. There was a ton of it on all the tanks especially in the ports. If you did not passivated then that’s why you have the spots on the bottom....

Thanks guys, I also reached out to SSBT and they echoed the TSP step is/was needed. I did not use TSP in my initial prep, just BKF, PBW and StarSan acid. Seems like TSP is also good for cleaning grout / tile and prepping paint surfaces, so I'm just going to buy a few lbs of it. Funny, they mentioned all of the existing oils etc. being food grade so while the beer might have a terrible tinny finish, it's still safe to drink.

I'm going to try TSP, followed by StarSan before he next brew day (perhaps this weekend?) and report back. There's no corrosion on the kettle but certainly some residue from not being properly passivated, I am hoping this will effectively end the surface/taste issues with the kettle.

Expensive lesson learned if so...

 

[Bilsch]

I had similar issues with new ssbt equipment and even more so with valves. There is a lot of residual cutting/machine oil everywhere especially inside the valves and ports. I find that dawn soap, hot water and lots of scrubbing worked the best. TSP didn't really get the film as well as I thought it should. Then the inside major surfaces with BKF for its fine abrasive quality and finally finished off with a hot 4% citric solution for the passivation.

 

[Rev2010]

I did not use TSP in my initial prep, just BKF, PBW and StarSan acid.

Not trying to be a negative Nancy here, but if you already cleaned it with BKF & PBW I can't see how TSP would change anything. BKF is pretty strong stuff. But, good luck! Report back.


Rev.

 

[Hermit]

Not trying to be a negative Nancy here, but if you already cleaned it with BKF & PBW I can't see how TSP would change anything. BKF is pretty strong stuff. But, good luck! Report back.


Rev.

Not to mention it didn't seem to abate any by the second brew.

 

[Vale71]

TSP is not going to remove welding material residue, only grease and oils. For metallic contamination you need to either manually polish or chemically pickle the surface.

I hate to say it but it looks like SSB just gave you a stock answer out of their FAQ...