Great video! Im about to passivate a few brewing items and have some questions. 1. Alot of my items are either 303 or 304 stainless. Do i understand correctly that passivating makes them more food safe and closer to 316 grade? 2. I have some equipment including a boil kettle that ive been using for years without passivating and it has some stuck on deposits. Would i be better off to not passivate it to avoid risking leaching out deposits after this long? Thanks!
Hey Blake! There is some evidence in the ASTM literature that passivating 303/304 leaches out the surface chromium and other nasties that can transfer to your wort. And it definitely makes it more corrosion resistant. That said, 316 is still the recommended material for direct food contact, but who can afford that? Lol To your second point, I wouldn't recommend passivating anything but a new pot or one that has been completely mechanically resurfaced. The acid will lift in some of it and deposit it everywhere I am afraid. Glad you found the video helpful. Make sure to follow all the recommended safety guidelines from the acid manufacturer.
@danjohnson8942 Excellent, that makes sense. The new piece I'm looking to treat is an Ss Brewtech unitank. They explicitly promote their use of 304 stainless so the lack of 316 made me nervous. The recommendation from their website is to passivate using 4% citric acid by weight and purified water at 150° for 30 min-2hrs. If i understand correctly that would mean 15 gallon vessel = 120 lbs of water to 4.8 lbs of cotric acid. Following that i plan to do a pbw rinse also at 150° and then purified water rinse as long as you agree
Great video! Im about to passivate a few brewing items and have some questions.
1. Alot of my items are either 303 or 304 stainless. Do i understand correctly that passivating makes them more food safe and closer to 316 grade?
2. I have some equipment including a boil kettle that ive been using for years without passivating and it has some stuck on deposits. Would i be better off to not passivate it to avoid risking leaching out deposits after this long?
Thanks!
Hey Blake!
There is some evidence in the ASTM literature that passivating 303/304 leaches out the surface chromium and other nasties that can transfer to your wort. And it definitely makes it more corrosion resistant. That said, 316 is still the recommended material for direct food contact, but who can afford that? Lol
To your second point, I wouldn't recommend passivating anything but a new pot or one that has been completely mechanically resurfaced. The acid will lift in some of it and deposit it everywhere I am afraid.
Glad you found the video helpful.
Make sure to follow all the recommended safety guidelines from the acid manufacturer.
@danjohnson8942 Excellent, that makes sense. The new piece I'm looking to treat is an Ss Brewtech unitank. They explicitly promote their use of 304 stainless so the lack of 316 made me nervous. The recommendation from their website is to passivate using 4% citric acid by weight and purified water at 150° for 30 min-2hrs. If i understand correctly that would mean 15 gallon vessel = 120 lbs of water to 4.8 lbs of cotric acid. Following that i plan to do a pbw rinse also at 150° and then purified water rinse as long as you agree