Kettle sours and aluminum kettles

[TravelingLight]

I'm getting ready to do my first kettle sour. I've read countless entries about not souring in an aluminum kettle. And it makes total sense. I get it. Therefore, I'm going to sour in a carboy.

My question is about boiling after it's soured. I know plenty of people do a no-boil, but I will be boiling. What about boiling a lacto-soured wort in an aluminum kettle? FWIW, I've already stripped off most of the oxide layer in my kettle from leaving oxyclean in the kettle overnight. And I've brewed plenty of beers since then with no issue. But I'm concerned about boiling something for 60 minutes with such a low ph. I guess I could boil it in my keggle if necessary (those things are SS, right?).

 

[crane]

Why boil for 60 min? If all you are trying to do is kill off the lacto, then you only need to bring it to a boil, then cool and transfer back to the fermenter.

I wouldn't think that a short time in the kettle would be a problem but I'm no chemist.

And yes kegs are stainless steel

 

[TravelingLight]

Why boil for 60 min? If all you are trying to do is kill off the lacto, then you only need to bring it to a boil, then cool and transfer back to the fermenter.

I wouldn't think that a short time in the kettle would be a problem but I'm no chemist.

And yes kegs are stainless steel

My thought as well, re: 60 minute boil. This is another's recipe, I was just looking at it. I'm curious now too why he does a full boil. But I'm going to ask...

 

[JosephN]

He might be doing a full boil to help cut down on the DMS from the Pilsner malts. Also boiling in the kettle won't be a big deal. If the aluminum isn't damaged from the oxiclean then you'll be fine. Oxiclean is also an alkaline chemical, while something like star san is acidic. I don't know how acidic star san is, but I know if left over night in aluminum it will pit it and cause it to start introducing white oxidized powder in your beer/wort. But like I said, if the aluminum is in good shape then boiling even for 60 mins should be a big deal at all.

 

[mabrungard]

I've done several Berliner's, but I 'kettle' sour in a corney keg. I do boil that soured wort to kill the lacto. My aluminum kettle has a nice brown patina on the interior from all the batches, so there is no aluminum contact with the soured wort. I don't believe using that kettle was a problem in that case.

If I had just cleaned my kettle to a shine, I wouldn't consider using it for a soured wort. The low pH would likely pick up some aluminum. The lowest pH that should contact aluminum is about 4.5. Most wort is not that low.

 

[TravelingLight]

He might be doing a full boil to help cut down on the DMS from the Pilsner malts. Also boiling in the kettle won't be a big deal. If the aluminum isn't damaged from the oxiclean then you'll be fine. Oxiclean is also an alkaline chemical, while something like star san is acidic. I don't know how acidic star san is, but I know if left over night in aluminum it will pit it and cause it to start introducing white oxidized powder in your beer/wort. But like I said, if the aluminum is in good shape then boiling even for 60 mins should be a big deal at all.

I've done several Berliner's, but I 'kettle' sour in a corney keg. I do boil that soured wort to kill the lacto. My aluminum kettle has a nice brown patina on the interior from all the batches, so there is no aluminum contact with the soured wort. I don't believe using that kettle was a problem in that case.

If I had just cleaned my kettle to a shine, I wouldn't consider using it for a soured wort. The low pH would likely pick up some aluminum. The lowest pH that should contact aluminum is about 4.5. Most wort is not that low.

These two posts seem contradictory, but I could be misunderstanding one of them, or both.

My aluminum kettle is not shiny and new looking. The inside is gray/brown and has no shine left on it. This is mainly due to me stripping the oxide(?) layer off months ago when I left oxy in it overnight. Ergo, I don't think there is anything left on the inside of the kettle to strip off. Based on that, Mr. Bru'n is saying I should be fine to boil in my kettle? Am I understanding that correctly? Thanks.

 

[crane]

A shiny kettle has no oxide layer. If it is grey/brown then that is the oxide layer

 

[TravelingLight]

A shiny kettle has no oxide layer. If it is grey/brown then that is the oxide layer

Well sheet. I have thoroughly confused myself at this point. I may just boil in the SS keggle to be on the safe side.