Acid mash! how to make?

I'd like to make a fruit beer with a pronounced acidity. I read about the possibility of making an acid mash.

that is, make a mash a few days before to be inserted in normal mash with an infusion of 90 minutes

have you ever done? What are the advantages and disadvantages? advice during the production?

You want to add acid malt to your mash. This will lower the acidity of the mash and you need to be careful because if you lower it too much the enzymes will not convert your grains. This is also not a good way to get a pronounced acidity because you run a huge risk of not having wort which converts and you kill off all of the lacto in the boil. What I would do is add lactic acid to the secondary before bottling to get a tartness or add lacto bacteria to a primary or secondary to get a sour. This will take a long time to get sour though.

I just listened to a BN podcast where they talked to someone from black star brew pub in austin, tx. He does a sour mash where the mash sits for a certain period of time to go sour, then sparges and boils...

You will want to here from someone who has had success with sour mashes, or experiment yourself, before investing in any huge projects. I made a sour mash beer once, and I have more knowledge on the subject now. It was foul. One of very few batches I have dumped. Doing a small sour mash, 1-4 qt, and adding it to your mash on brew day may be a solution. Perhaps someone with more experience will chime in but I recommend small scale experimentation before you go for a full batch of sour mash beer.
GL

I know Papazian has a good method to it in his book The Joy of Homebrewing.

Ok, thanks for the answers, I have used in the past the lactic acid and the brettanomyces, that i prefer, managing to pull off that aroma that is used to call "stale".
But I want to try something new. interesting the technique of black star, but I have fear that a mash stop for days and then simply boiled can also give strong tastes of oxidation. i will try, as says bbrim, to do a little sour mash and infect half of the main mash, the other half I will follow standard procedures, adding in a secondary Brettanomyces. I will use for both in primary wlp0510 so I can see the difference.

Yeah, I think a small sour mash added to the rest is probably a good way to start off. Set your sour mash up like you normally would at whatever temp you mash at, hold it for 30min. or so to get some conversion, then transfer it to a small cooler if you've got one. Once the temp hits about 100, toss a handful of grain into there and lay a big piece of saranwrap over the top of the mash and close up the cooler. The grain will introduce a bunch of different bugs, and the temps will make the lacto nice and happy. Putting saran wrap on top will keep the oxygen away and inhibit acetobacter from getting a foot hold.

Then come brew day, just drain and add the sour mash to the boil kettle like you normally would along with your other wort. You could even sparge the sour mash if you wanted to. I wouldn't bother adding the sour mash to the regular mash unless you are worried about conversion not being complete in the sour mash. Although if you're planning on adding brett anyways, it will eventually take care of your dextrins.

dear erikpete18, I'm Italian and sometimes I do not totally understand what you write to me. I think I understood your message, but the saran wrap put me in a crisis. What is the saran wrap? I was thinking of something strange that you Americans have, something you use in your brewing .. and it is just a roll of plastic wrap.

However, I thought of something like 17 pounds of Pils in 13.5 gallons of water, bring to 140 degrees... only 30 minutes and then cool? after which I throw a handful of grains inside and close with saran wrap
3-4 days later i will realize my beer, i drain my mash and add it during the normal boiling.

is everything ok? I hope it

Ha, yeah, I maybe should have specified a little more on the saran wrap! Even something like tin foil would work, you just want to limit oxygen's access to the mash.

The only problem with your plan is that I'm not sure how big of a batch you are doing. If 17lb/13.5 gal is only part of your batch, then you should be fine. If you are planning on souring the whole batch, you'll probably want to mash for the full hour to make sure you get proper conversion. 30 min. might even fully convert, but if it doesn't you are going to be left with some longer chain dextrins and starches.

If the sour mash is only a small portion of the full batch and you're planning on adding some brett later, a few extra dextrins won't matter much. However, if you're thinking about souring a large portion of your mash, too many extra dextrins would be bad in the final product since the brett would take a long time to get to all of them. If a larger sour mash or souring the whole mash is the goal, you might want to mash a full hour to make sure conversion is complete. That way you'll have plenty of starting sugars for your yeast. If you wanted you could mash at a higher temp to leave some dextrins for the brett. Then go ahead and just let the mash cool down gradually until it hits 100 or so, toss some grain in and cover it up. Wait 3-4 days for it to sour, sparge like normal, and you should be good to go!

Also a note, there's a lot of stuff going on in the sour mash and it can really start to look/smell funky. Normally that's not a problem, and boiling removes a lot of those funky flavors and the yeast use up a bunch of the other stuff. But since you are essentially infecting it for a few days, you can wind up with some nasty batches like bbrim apparently had. Just a fair warning not to toss it too soon, but also to watch out! That being said, sour mashes generally give you a flavor you can't get with just purchased bacteria or lactic acid, so definitely go for it if its up your alley!

use lactobacillus/brett along with your regular yeast that is typical, for guezes and lambics!!!! acid malt is used for mash PH control, it was created to coincide with the german brewing laws for adjunct restrictions, it was not meant to give acid flavor profile, it will be more astringent on high percentages for the palate to notice. and it will compromise your conversion in the mash.

the use of acid malt is also common here in Italy, when you can not lower the pH of the wort, but this is not my main target. I need a true infection, an infection that just give me a different taste from Lactobacillus / brett. for this I would try to divide the beer in two, one with the addition of sour mash, the other only with the yeast. then in secondary brett for both. so that I can understand what the real contribution of flavors that can give the sour mash

for erikpete, thanks for the advices. the amount of sour mash is for a mash about 3.2 gallons

one last question.
there is a real possibility of a difficult conversion in the main mash?

The trouble with conversion in the main mash would depend on how acidic your sour mash gets and how much of it you add to the main mash. If the sour mash is too acidic and you add the whole thing to the main mash at the start, you might drop the pH below the optimal range for your amylases to work. A low pH mash might require a longer conversion rest to make sure everything gets converted, and an iodine test would probably be a good idea. If you've got a pH meter or pH strips they would tell you about where you're at and whether or not you need to worry.

The other option would be to add enough of your sour mash to get down to about 5.2 pH (especially if you normally have to add something else to reach that pH), and hold that mash for an hour to convert everything in the main mash. Once the main mash has converted, then you could add in the rest of the sour mash and hold it for another half hour to try to finish converting anything that was left unconverted in the sour mash. After that, proceed as normal and prepare for delicious beer!

Tabernae said:

the use of acid malt is also common here in Italy, when you can not lower the pH of the wort, but this is not my main target. I need a true infection, an infection that just give me a different taste from Lactobacillus / brett. for this I would try to divide the beer in two, one with the addition of sour mash, the other only with the yeast. then in secondary brett for both. so that I can understand what the real contribution of flavors that can give the sour mash

for erikpete, thanks for the advices. the amount of sour mash is for a mash about 3.2 gallons

one last question.
there is a real possibility of a difficult conversion in the main mash?

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I see what we call saran wrap called cling wrap in some parts of Europe. Whatever you call the plastic wrap you would use to wrap food for storage in the fridge.

I have had good success with mashing part of the grain, sparging, giving the wort a brief boil to sanitize, then adding a few fresh grains to the wort to infect it. I guess it's more of a sour wort than a sour mash process but it has the same effect of souring without the nasty infections sour mashes sometimes get. I keep air out by souring in a growler with foil over the mouth so there is very little oxygen exposure. Then on brew day do the regular mash and then add all the wort -- sour and unsour -- in the kettle and boil as usual. No nasty off flavors, no problems with conversion.

If you are going to add the sour mash to the regular mash I would advise adding it right before sparging to make sure you get proper conversion.