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The Truth about Acidulated Malt: What Brewers Need to Know

Updated: Mar 27, 2023

If you brew to the Reinheitsgebot this may not be for you.

By Chris Lewington


Acidulated malt, talk to me.

Acidulated malt is created by two different methods.

1) Germinating malt is sprayed with a lactobacillus culture and allowed to ferment, then kilned.

2) Kilned malt is steeped in hot water to allow lactic acid bacteria to create lactic acid.

Cool, so why do brewers use it?

Great question thanks for asking.

We all know the Reinheitsgebot is a German Law preventing German brewers using anything outside of the four main ingredients of beer.

Acidulated malt was created to give predictability and stability of mash pH using predetermined acidity levels disclosed prior to arrival to the brewery. For those German brewers not using their own wort derived lactic acid cultures to acidify wort this is a useful way of achieving proper mash pH.

There has been a very misleading approach to advertising Acidulated Malt in foreign markets. Often you will see these posted in the descriptions of Acidulated Malt sales literature.

“Contributes to the optimization of the mash conversion”.

“Enhances enzymatic activity in mash and improves extract efficiency”.

Whilst on the surface they are true, in fact they are misleading.

Acidulated malt will achieve these statements but it's having the correct mash pH that is the cause of these effects - not the malt itself.

The method of acidifying your mash is not relevant to the gains of having a correct mash pH. (t-shirts coming soon)

And as you see below there is absolutely zero reason to use Acidulated Malt unless you are bound to by law.

Why Acidulated Malt should not be used in the brewery:

  • The emissions in growing, manufacturing, transporting and then using any type of malted barley are huge. Scope 3 emissions are the biggest proportion of a breweries carbon emissions.

  • Zero extract potential meaning you get no gravity points from acidulated malt (in any method of production)

  • Acidulated malt is expensive.

  • There is zero evidence of any unique flavour to acidulated malt. Especially in the low % of total malt bill. (The flavour of acid in a beer is achieved in more resourceful ways)

  • Cannot be used post mashing in

  • There are a lot of significantly more resourceful ways of achieving your target mash pH.

Cool, so you've ruined acidulated malt. What are my alternatives?

Luckily there are alternatives that require less carbon emissions to produce AND are cheaper to buy, transport and store.

Food Grade Lactic Acid:

Skip the entire wasteful and expensive malting/acidulating process and add food grade lactic acid directly into your mash.

It requires ~78g of lactic acid per 100kg of malt to drop mash pH by 0.1 (Lactic Acid Strength dependent) (calculator supplied later)

As with acidulated malt there is a flavour threshold. The theoretical threshold is 400mg/l of lactic acid in beer.

I have provided a calculator in the Brewers Tool Box Section. The calculator that will inform you if you are in danger of adding too much.

Food Grade Phosphoric Acid:

If you require a large pH drop in your mash you may want to out lactic acid all together and move to Phosphoric Acid. Even less is required than lactic acid the taste threshold is not relevant in beer.

It requires ~38g of phosphoric acid per 100kg of malt to drop mash pH by 0.1 (Phosphoric Acid Strength Dependent)

The same calculator will provide guidance with additions.

Other options

Of course there are other acid addition options and of course textbook salt additions. But the purpose of this blog post is not to rewrite your water chemistry. Simply to get you to replace acidulated malt with food grade acid additions.

Food Grade Lactic Acid & Phosphoric Acid are readily available from your current Brewing Supply Store.

Emit less Carbon & save cost by switching Acidulated Malt to a Food Grade Acid now.

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