Mash Liquor

The subject of liquor treatment is a massive can of worms and one which I don't know enough about to open it up.  So, I'll keep it very brief and explain what I do.

For many years I brewed with whatever water can out of the tap and I was very happy with my beers.  However, over time I've raised my game somewhat and expect more from my beers.  Liquor treatment is one way of turning good beers into great beers.

Before beginning brewing it's advantageous to remove any chlorine from the liquor. There are a number of ways you can do this; boil the liquor for 15 minutes then allow the carbonates to settle out, add a campden tablet and leave for half an hour or so, leave the liquor to sit overnight or filter with a carbon block filter.  Failure to follow one of these procedures with expose your beer to the risk of tasting like TCP once it's been fermented.

Once the chlorine has been remove, in order to get an efficient mash without extracting too many tannins from the grain husks you should aim to maintain the mash pH at about 5.3.  Sounds easy doesn't it.  Well it's not!  The pH of the mash is predominantly decided by the type of water you have and the acidity of the grains you are using.  The darker the grain the more acidic it is.  What this means in real terms is that my water is very hard and I struggle to keep the pH down below 5.5 on pale ales and lagers without acidifying the mash in some way.  It is, however, well suited to stouts and old ales.  That's great but I prefer pale ales! 

One way of lowering the pH is to add CRS (carbonate reducing solution) to the mash liquor to knock out the carbonates and then add DLS (Dry Liquor Salts) to the grist before mashing.  Details of how to do this can be found here.

Alternatively you can use a food grade acid such as lactic or phosphoric acid to reduce the pH of the liquor prior to mashing.  I initially chose to use lactic acid for no better reason than that's what I was sold when I discussed it with Di in the Homebrew Shop in Farnborough.  This worked very well but I've since moved over to using CRS and DLS.

Here you can see that having mashed 8 kg of pale malt and 150g of crystal malt I measured the mash pH and was pleased to find I had pH 5.17 after having treated my liquor with lactic acid to pH 5.95.

The liquor treatment does seem to require a bit of trial and error but I think it's worth giving it a go as the beers do tend to benefit from it.

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