John Palmer and Residual Alkalinity In Brewing Water

I don’t usually include news and reviews, but having got back from the International Craft Beer Festival in Buenos Aires I thought it was worth sharing the highlights here on the blog.

Water is a key element of brewing and, after John Palmer’s talk at the event, I’m now inspired to find out more about it.

john palmer speaking at the buenos aires craft beer festival: the audience
The Somos Cerveceros International Craft Beer Festival is primarily aimed at home brewers, and features a variety of activities including speeches and a brewing competition.

The Barba Roja brewery hosted the central event, a series of talks and presentations to brewers.

buenos aires craft beer festival

As well as the theory, there was an exchange of beers by home brewers from throughout Argentina. They were all great.

I saw talks on yeast by a speaker from Fermentis and laboratory tests for home brewers by Gabriel Reynoso from the Antares brewery.

Both contained useful tit bits that’ll feed into my brewing in due course.

Celebrity brewer John Palmer gave the main talk of the day. Most famous for his book How To Brew, here he spoke about residual alkalinity in brewing water.

It’s an interesting topic.

Water is one of the more neglected beer ingredients (at least by me), depite making up the bulk of any brew.

Although you can usually make good beer with any water, if you use water with the right minerals for the style you’ll lift the beer to another level.

I’m going to experiment with Palmer’s advice myself, before presenting any conclusions in future articles.

In the meantime, here are some of the highlights to whet your appetite.

Mash pH and Minerals in Brewing Water

The mash is where beer making begins, and for it to work well it must have a pH in a particular range.

The mash pH determines the fermentation pH, and then the beer pH. If you get the mash right the rest takes care of itself.

Mash pH is a product of three things:

  • calcium
  • magnesium
  • alkalinity

There are other things in brewing water (or added to it by brewers) that affect the flavour, but not the pH: sulphates accentuate hop bitterness, chlorides maltiness.

john palmer talking about residual alkalinity and brewing water

When it comes to preparing your brewing water you can add minerals to suit particular styles. Calcium chloride for a Bock, or calcium sulphate for an IPA, for example.

Hard water is good for brewing because it has a lot of calcium and magnesium. Soft water can have clarity problems, due to the lack of calcium.

When looking at water additions you’re mainly concerned with calcium because magnesium is provided by the malt.

At room temperature the ideal mash pH is 5.2 – 5.6, and this changes to pH 4.9 – 5.3 at mash temperature.

PH can be measured with a simple testing kit.

If you overshoot the pH, the beer will taste fine but it will be lifeless. If you get the pH right, the full range of malt and hop flavours come through.

Residual Alkalinity

Residual alkalinity is what’s left after the reaction between chemicals in the malt and water has taken place.

  • A high residual alkalinity is good for dark beers.
  • A low residual alkalinity is good for light beers.

The key take away Palmer left us with was:

Residual alkalinity should match the style you’re brewing. Mineral additions are to taste.

If you want to find out more about residual alkalinity, Palmer has a section on his How to Brew website.

I’ll leave it at that, as there’s already more than enough here to explore.

I’m still digesting the information and will test and write about it in future articles.

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