Acidulated Malt vs. Sour Mash

Brewing a KY Common soon and hoping to get some insight on sour mashes. I have done my homework and feel confident that if I needed to, I could handle a sour mash with fair ease. However, I am curious if it would be easier to just use acidulated malt. Any thoughts on this?

If I can in fact use acidulated malt in place of a sour mash, is there a conversion formula? I think that I am mashing about 10% of the grains in a sour batch. Should I replace that with 10% acidulated?

Thanks for the insight.

I tried a sourmash similar to O'Daniel's methods on a whim. We brewed a Tripel with 23# of grains and I was thinking that with 75% efficiency, there were still a lot of sugars left in there. So i heated a couple gallons of water, pitched a pound of fresh 2-row poured it onto my bag in a round cooler (I do BIAB) and let it sit 24 hours then brewed a beer from the runnings. VERY GOOD. I do this after almost every beer now. I made a great sour from the spent mash of Cream of Three Crops. The one thing I am going to add is some torrified wheat, the head develops then falls quickly because (I think) the proteins must get washed out in the first beer. I usually use grains of paradise and/or coriander to get a little spice and very little hops. The result is a sourish, refreshing, light beer that even BMC drinkers usually like.

Just a thought of a cheap way to experiment!

Acid malt and an sour mash are different animals. Acid malt has some lactic acid (I believe 1 - 2% by weight) sprayed on to it and it is used to adjust mash pH.

A sour mash is a mash that is exposed to the local microorganisms that will eventually 'contaminate' the mash and make is sour, exactly to how lambics, Flanders, and the other related styles are made in Belgium.

If you want to brew a sour mash, I wouldn't substitute acid malt for the sour mash. Research how (sounds like you have already) the proper way to do a sour mash. They are pretty easy to do.

avidhomebrewer said:

exactly to how lambics, Flanders, and the other related styles are made in Belgium.

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While I've never used acid malt or done a sour mash, I have to disagree with this statement. Lambics are made using a process called "turbid mashing" and is used because of the the large portion of unmalted wheat that is used in the mash. While the wort is cooled, it is exposed to wild yeast and bacteria which impart the sour character. Other sour Belgians typically use similar yeasts and bacteria to achieve sourness.

The only style I know of that uses a sour mash to achieve sourness in Berliner Weiss (though I am sure there are others that I am just not aware of). With a sour mash, lactic acid are naturally occurring in the grain which are not killed because the wort is never boiled. The lactic acid makes its way from the mash into the fermentation imparting the lactic sourness.

No.

A sour mash is some portion (as low as 10% or as high as 100%) of the grain mashed and left overnight or longer (up to 3 days) to sour. It is then boiled and made into beer. Sour mashes are very unpredictable in my experience, mainly because it is difficult to maintain an elevated temp for a larger mash over long time periods. When a sour mash goes bad, it goes very bad.

Sour malt is, as a previous poster noted, sprayed with food grade lactic acid at about 2% by weight. Beers soured with sour malt are one-dimensional in my experience. Note that with a Kentucky Common, you're probably just looking for "tart" and not sour.

The sour beers of Belgium are *usually* fermented normally, then soured in barrels. Lambics are an exception here as in just about every area- they are exposed to the local microflora and go through a complex biological process.

Now. When I tried a Kentucky Common, I went whole hog. 8 pound grain bill, 100% sour mash for 3 days. I just wrapped the cooler in a blanket and went on vacation- it dropped from 150 to 105 over 3 days. It was very tart, but not what I would call "sour". I would estimate it was about as sour as 1500ppm lactic acid would give.

Now with 2% sour malt at 10% of the same 8lb grain bill, I get an estimated (8lb/bill)*(.10 1/bill)*(16oz/lb)*(28.3gm/oz)*(.02 lactic)/(20 liters/batch)*(1000ppm) = 360ppm lactic.

Translation: I would not expect this beer to be particularly sour. For comparison, a truly sour gueze is up around 4000ppm, while a berliner wiess might be somewhat less.

It all depends on what you're looking for, though. I believe ODaniel does 2% sour malt in some of his, which would be just enough for a subtle bite. If you're not a huge sour fan but want a little bit, another option would be to start low and dose with 88% lactic at bottling to get it higher if you want.

In terms of taste quality, I would rate a well-executed sour mash = lacto d. > sour malt > 88% lactic.

Hopefully some of this is helpful to you.

I think of acid malt as the equivalent of an acid rest during the mash process. Not so much a flavor component as it is an adjustment for pH. I think of a sour mash as a flavor (as well as a pH) component. Obviously an acid rest is a brief sour mash and conversely you could use enough acid malt to affect flavor.

That's not a perfect projection, but that's how I think of it in my head.