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General Category => All Grain Brewing => Topic started by: dean on January 27, 2010, 01:00:56 PM

Title: acid malt and lactic acid?
Post by: dean on January 27, 2010, 01:00:56 PM
Is acid malt the same as acidulated malt?  I was looking at a description of acidulated malt and it sounds like its soaked in lactic acid? 
Title: Re: acid malt and lactic acid?
Post by: Kaiser on January 27, 2010, 02:36:34 PM
Yes, they are the same. Acid and acidulated malt are produced by spraying them with lactic acid and drying it. The acid content is about 3% by weight.

Kai
Title: Re: acid malt and lactic acid?
Post by: denny on January 27, 2010, 04:16:30 PM
Never used acid malt, but I use lactic acid on my lighter beers.  It would seem to me that lactic acid additions would be easier to control than using acid malt, where you have to decide on an amount before you actually know what your pH is.  I guess that assumes you're using the acid malt for pH adjustment and not taste.  So, those of you who have used acid malt, how do you go about deciding how much to use?  And if acid malt is malt sprayed with lactic acid, what advantage does it have over adding lactic acid directly?
Title: Re: acid malt and lactic acid?
Post by: Kaiser on January 27, 2010, 04:34:46 PM
Never used acid malt, but I use lactic acid on my lighter beers.  It would seem to me that lactic acid additions would be easier to control than using acid malt, where you have to decide on an amount before you actually know what your pH is.  I guess that assumes you're using the acid malt for pH adjustment and not taste.  So, those of you who have used acid malt, how do you go about deciding how much to use?  And if acid malt is malt sprayed with lactic acid, what advantage does it have over adding lactic acid directly?

You can determine the necessary amount of acid malt by using a water spreadsheet. If you know your current residual alkalinity you can determine how much acid you need to lower it to your target RA. That amount of acid can be calculated as 88% LA or acid malt. I have also used acid malt ad-hoc after testing mash pH but these days I prefer figuring out the necessary amounts ahead of time so I don’t have to take care of it while brewing.

Here are some numbers:

Each kg of acid malt can neutralize ~17-18 g of alkalinity as CaCO3. I.e. to lower a residual alkalinity of 100 ppm to -100 ppm in 16 l water you need to neutralize 200 mg/l * 16 l = 3.2 g as CaCO3 which takes ~ 0.18 kg of acid malt.

I like the “elegance” of using acid malt though I also have 88% LA at home. If you use strong lactic acid you need to be able to measure very small amounts 1-2 ml at a time while acid malt can simple be weighed with a scale you already have.

Kai
Title: Re: acid malt and lactic acid?
Post by: denny on January 27, 2010, 04:42:20 PM
Thanks for the explanation, Kai.
Title: Re: acid malt and lactic acid?
Post by: NorthernIke on January 27, 2010, 06:18:59 PM
I like the “elegance” of using acid malt though I also have 88% LA at home. If you use strong lactic acid you need to be able to measure very small amounts 1-2 ml at a time while acid malt can simple be weighed with a scale you already have.
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I bought a syringe at Walgreens.  It goes up to 3 ML in 1/10th ML increments.  It was cheap and works great!
Title: Re: acid malt and lactic acid?
Post by: ndcube on January 28, 2010, 12:14:12 PM
If you use strong lactic acid you need to be able to measure very small amounts 1-2 ml at a time while acid malt can simple be weighed with a scale you already have.

Do you know how much a ml of 88% LA weighs at, say, 40F?

It's probably easier for me to weigh it on my gram scale unless I steal one of our baby medicine doppers.  I'll have to see if we have an extra one.
Title: Re: acid malt and lactic acid?
Post by: Beertracker on January 28, 2010, 04:56:28 PM
Good stuff Kai! I typically only use acid malt in low temp dough-in situations esp. decoctions e.g. hefeweizens. Great for rye beers too! Don't ask me why?   :-\   
Title: Re: acid malt and lactic acid?
Post by: denny on January 28, 2010, 04:57:47 PM
Do you guys use acid malt for flavor or for pH adjustment?
Title: Re: acid malt and lactic acid?
Post by: a10t2 on January 28, 2010, 05:21:28 PM
Do you know how much a ml of 88% LA weighs at, say, 40F?

Looks like it should be right around 1.22 g/cc. http://www.epa.gov/hpv/pubs/summaries/lactacid/c13462rs.pdf (http://www.epa.gov/hpv/pubs/summaries/lactacid/c13462rs.pdf)
Title: Re: acid malt and lactic acid?
Post by: Beertracker on January 28, 2010, 05:23:52 PM
Do you guys use acid malt for flavor or for pH adjustment?

I typically use it for early mash pH adjustments, but regarding my German wheats it tends to "round-out" the body/texture so maybe both?  :-\