sour mash questions

Before I begin experimenting with sour mashing I have a few questions I have not seen discussed yet (or just haven't searched long enough).

1. Does a sour mash produce gases that need to escape from whatever vessel the sour mash is in? Or can I seal it up while it's souring?

2. If I sour a good portion of my grain bill will the PH be too high for the yeast to work?

3. The grain and liquid that is soured goes into the mash, but this grain will not contribute any more sugar/fermentables to the recipe correct? the bugs have eaten the sugar already.

4. Has anyone ever tried fermenting a standard beer all the way through then, during kegging time, taking a separate small sour mash, strain it, boil it, cool it and blended it into the keg?

Thanks for any help guys!

PS - I do plan on using roeselare or lambic blend to make a more dynamic sour also. Just want to try the quick version too.

No expert, just a recent one under my belt. No scientific supporting data/theory, just my one time experience:

1. I used a cooler, lined the surface of the mash with plastic wrap, inserted a remote thermometer probe, and closed it up. The cooler seals tight, but surely is not a pressure vessel and no noticeable pop or pffsst when opening it.




I checked temp occasionally. It dropped about 6F per 12 hrs. (not much mass, 7lbs grain and started thick). I added a little near boiling water to raise to around 110, and left it closed for another 12 hrs. Always kept it above 100F.

2. I soured 100% of my grist. No issues for yeast although I over pitched with a massive yeast cake I had. I didn't measure the pH.

3. As far as fermentables go, there is plenty left behind. I had less pre-boil water than my recipe called for, but I had no problem with hitting my OG. I usually formulate recipes with Jamil's volume profile: 7 gal preboil, 6 post, 5.5 transferred, and 5 packaged. Since this was a short boil, I still finished with over 5 gallons finished beer.

4. I haven't tried it.

My was a inoculated with yogurt, not raw grain, so only lacto at play.

Hope that helps allay concerns.

WVBeerBaron said:

Before I begin experimenting with sour mashing I have a few questions I have not seen discussed yet (or just haven't searched long enough).

1. Does a sour mash produce gases that need to escape from whatever vessel the sour mash is in? Or can I seal it up while it's souring?

2. If I sour a good portion of my grain bill will the PH be too high for the yeast to work?

3. The grain and liquid that is soured goes into the mash, but this grain will not contribute any more sugar/fermentables to the recipe correct? the bugs have eaten the sugar already.

4. Has anyone ever tried fermenting a standard beer all the way through then, during kegging time, taking a separate small sour mash, strain it, boil it, cool it and blended it into the keg?

Thanks for any help guys!

PS - I do plan on using roeselare or lambic blend to make a more dynamic sour also. Just want to try the quick version too.

Click to expand...

1) take a look at the above pic - perfect imo. you want to cover it. it doesn't need to be air tight, but you need it sealed up nicely with saran wrap or something.

2) that's my understanding, but you don't need much to make it overpowering - be careful

3) i drain and sparge my sour mash and add the liquid it as a late addition to my boil.

4) nope. but i don't see why you couldn't. might not have the complexity of bug sours, or even sour mashed sours, but why not try it. (i'd try it on a pint first)

My most recent sour mash was for a berliner weisse. I mashed 7# of grist at 151F for an hour then stirred for about 10 minutes to bring the temp down to 130F. At that point, I laid saran wrap over the mash, pushing out all the bubbles. I then poured some seltzer water over the top (not too much) to help expel any O2. Seal the mash tun and threw it in an un-operational vehicle. During the day, temps inside the vehicle reached 120F which helped keep my mash temp between 100-130 degrees. It ran for about 40 hours before it went into the boil kettle. Smelled of clean, creamed corn, no foul aromas. Fermented with wyeast german ale and even with an OG of 1.041, the 4 gallons of wort blew off the stopper from the 6gal carboy within 8 hours. Very violent fermentation. Within a week the gravity dropped to 1.010. So I am confident that there are plenty of sugars left for the yeast.

WVBeerBaron said:

4. Has anyone ever tried fermenting a standard beer all the way through then, during kegging time, taking a separate small sour mash, strain it, boil it, cool it and blended it into the keg?

Click to expand...

I think everybody else answered the first three questions very well. I haven't done exactly what you're asking about here but my usual quick souring technique is to mash part of the total grain bill, sparge, boil and then cool and pitch some grain into it and let just that portion sour. It's more of a sour wort than sour mash. Once the portion is nicely soured after a few days I begin the normal brew process and add the soured wort to the main boil at the beginning. I've soured as much as half the total volume that way.

I've never done a regular sour mash to compare how sour the mash gets versus the wort method but I've been happy with my process. It's much more controllable and I only have theories/guesses about why I don't have the problem with my sour wort getting nasty that some people experience with sour mashes.

Just another option to consider.

You could blend in the keg like you're talking but one thing to keep in mind is lactobacillus usually only ferments simple sugars and will leave behind the malt sugars, so without also fermenting that sour portion you may end up with more of a sweet and sour flavor contribution than just a sour contribution. May not be bad but it may through the beer off and I'm not sure how you would correct that without making it worse. Then again, half the fun of homebrewing is experimenting.

Hey - thanks for the help everybody! You guys have answered my questions.

Sounds like escaping gases are not formed while the grain or wort sours. I have a plastic collapsible water container that I will use. I can add the grain or wort to be soured, then push out all the other air and screw the lid on tight and place inside my 10 gallon water cooler with 110 degree water for several days, probably adding water every 12 hours or so but the collapsible container could be submerged and it sounds like it will not explode since there is no gas to escape.

Sounds like PH is not an issue, even if I sour my entire grain bill.

Also, sounds like there are plenty of fermentable sugars left after souring for the yeast to eat so that's not an issue.

Thanks again for the quick responses

I've seen the seltzer trick posted a few times. Is it worth while? Cons?