Monday, 14 September 2009

Crystal malt is not fermentable

Well, according to "the world's top beer writer" Roger Protz, writing in the latest issue of What's Brewing it isn't.

Oh yes it is, according to anyone who's ever brewed with it.

For those of you that don't know what I'm wittering on about Crystal malt is a type of malt used in brewing that has been stewed and caramelised before it gets to the brewery. This does, as Roger Protz says, give colour and caramel flavour to finished beer. It does not mean it has no fermentable material though.

According to the excellent Murphy & Sons website Crystal malt has 275 litre degrees per kg of fermentable extract, compared to Pale malt with 305. You don't need to understand what litre degrees per kg means to see that though Crystal malt has less fermentable material it's certainly not devoid of it.

You really need to have made beer before you can start to understand it.

7 comments:

  1. He's the ex-editor of the CAMRA newspaper and current editor of the Good Beer Guide.

    Like the late great Michael Jackson he's a journalist by profession, not a brewer, so prone to making technical gaffes.

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  2. Doesn't taking Crystal Malt make your teeth fall out..?

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  3. lol. That's Crystal Meth!

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  4. Sorry guys.... it's not that straight forward and Roger Protz was indeed partly right. Firstly the figures on Murphy's site are extract figures and as all brewers know only around 65-75% of this is actually in fermentable form i.e. C1, C2 or C3 saccharides. The rest being non fermentables such as proteins, dextrins etc. Cara/Crystal malts of low colour i.e. reduced Maillard product content and less possible starch retrogradation would offer up 50% fermentable extract. By the time the colour and Maillard concentration gets to around 400EBC there is virtually nothing left that is fermentable, perhaps 10%. Weyermann in Germany clearly believe that their Cara malts contain zero fermentables but this could be because of the low level of modification in their raw malt. There are a couple of papers out there on this. Happy Brewing!

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  5. Sorry to come in so late on this one ;-). It's really not as straight forward as you think and Roger Protz is indeed right, or at least partly.
    Firstly not all extract is fermentable as all brewers know, so Murphy's site shows total extract and we all know only around 65-78% is fermentable C1, C2 or C3 sugars. The rest being proteins, tannins, dextrins, glucans, amino acids etc.

    Crystal and cara malts are similar with crystal being made from a highly modified malt and the process is more fully completed in the formation of the "crystal". Weyermann in Germany state that their caramalt has no fermentable extract apparently.

    Anyway any crystal/cara of low colour (10-30EBC) should produce 50% or so fermentable extract but by the time the colour approaches 400EBC this is reduced to almost <5%. Increased Maillard reactions and a degree of starch retrogradation all play a part.

    Happy Brewing! ;-)

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  6. Thanks Anonymous, sometimes I do go off on one before I've thought it though properly. Still, that is what the internet is for!

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