Nervous about souring

So, I have a stout in the bucket that is ready to bottle. I was planning on adding some lactic acid to the bottling bucket to give it a touch of sour like in a Guinness, but Austin Homebrew backordered my lactic acid. I don't really want to wait any more because it's ready to go and I don't really know when the backorder will come.

After talking to some homebrewers at an Oktoberfest last weekend, one of them recommended souring a pint or so and then adding it to the bottling bucket.

My question to you all is - how do I sour it, just leave it out uncovered? And also, what I am most nervous about, does this have a chance to infect the rest of the batch once it is added back in?

The sample for the FG test was really good, and I would hate to ruin this batch. It's my first stout (AG) and I am leaning toward just bottling it without any souring.

[7# British 2-row, 2# Flaked Barley, 1# British Roasted Barley, 1oz EKG for 60m, 1 oz Willamette for 60.]

Check out the jds blog. He's got a great sour stout...I think he soured before the boil tough. I'd be pretty anxious about souring after the boil too. I'd be affraid that it'd get wicked sour before it stopped.

What you could do.... is mix up about 1qt hot (150-160*F) water and about .75lb of 2-Row. I'd let it sit for at least 2 hours, and start cooling off.. then I would add another handful (call it 1/8lb? just a rough palmful) of freshly-crushed 2-Row to add the lacto bacteria back in.
I'd cover it and let it sit in a glass container for between 18 hours - a couple days. Let it get good and stinky. Then I'd drain the sludge through a strainer, and boil the resultant sour liquid for at least 15 minutes to break down the bacteria. That way you get a good "sour shot" but are sure that the lacto is dead once you blend it in.

Cool wort, and then pitch into the bottling bucket. You could even gently mix the wort with it, adding a little at a time, till you get the taste level you like.

The above procedure is just what I would do if I were in exactly the same spot. As BK said, it's probably best to do it before fermenting?

I checked out the jds blog, Big K, and yeah - it looks like he sours a bit before the whole mash process, kind of like making acidulated (sp?) malt on his own. Presumably, then, the boiling process would kill any nasties but keeps the sour taste. I'm real leery of doing it the other way around. I figure that anything that likes the pint and turns it sour would just go nuts with a whole 5 gal to work with.

Of course, then again, it would only be with the 5gal for the short process of bottling and then only have 12 oz or so to go nuts in.

Oh, and Chriso - I like your idea too. However, I don't have any grains left and my only LHBS within 1.5 hrs or so closed down. So that's out.


I'm probably going to save the whole souring process for the next time I make stout and just bottle this one as is.

I'm souring with yogurt culture, then without boiling, adding sacch. All the lacto spp will either be killed by the decreased pH or increased EtOH as a result of the sacch fermentation.

Chriso has the best suggestion, IMO. You might be able to get away without the sprinkle of malt, but you'll have better luck if you can hold it in the right temp range. I think I held mine at something like 122f and it came out perfectly sour with no funky stuff.

It totally depends on what you're going for. If you're going for a sip and "oh, that's noticeably sour", don't do what I'm doing. I on the other hand, am going for a sip and a "sweet **** that is sour".

If you want I could mail you my bottle (unopened) of lactic acid (i wont need it for a bit, +my lhbs is around the corner). I've mailed things to Newport and it gets there second day via priority mail.