Anything I’m Fermenting

March 12, 2009

Absolutely! Dry Beer.

Filed under: Brewing — iwouldntlivethere @ 6:41 pm
Tags: , , , , ,

Rather than respond to Sjoerd’s question in the comments, I think it is worth discussing it in it’s own blog post.

Here’s the question (I’ve edited it a bit to summarize):

I wonder if it is possible to create an absolutely dry beer, by first doing the alpha-step on 73 degrees, and then adding beta-amylase enzymes and continue mashing at 60 degrees. I remember reading that enzymes reside in the liquid parts for the most. Most of the starch, however, resides in the non-liquid parts.

So it would be something like this:
Heat to 60 C and mash it for 10 minutes. Drain and save half of the liquid. Raise the heat of the remaining mash to 73 C and let it rest for one hour. All the starch will now be converted by alpha-amylase into long-chain sugars, but the beta-amylase is denatured. Let the mash cool back down to 60 C, and add the remaining part of the liquid in which there still is a lot of active beta-amylase.
Now we can start the beta-amylase rest, which will convert the long-chain sugars into simple sugars. The only starch left should now be the starch from the liquid that was set apart, and I believe that this is not much.

What are your thoughts on this?

It is an interesting proposition – in essence that you would be doing a backwards multi-step mash. I did a quick search for this idea on Google, but nothing really came up. I may not be searching using the right terms though. But it does seem as though it is not being discussed on home-brewing forums. (I’ll just venture to suggest that this may be because very few home-brewers can directly heat their mash-tuns effectively, and of those that can (using computerized recirculating wort systems) may find it difficult to remove wort, then add it back later. Just guessing though)

I think the theory behind your proposal is sound. The only problem I see is that a lot of the starch does actually dissolve into the liquid before being broken down into sugar (this is proven by starch conversion testing – the iodine readily reacts with dissolved starch at the beginning of mashing). So a large part of your starch will have to be mashed in a normal method (it will sit with the beta-amylase while the rest of the mash is being heated to 73 C). To convert this dissolved starch, you would have to then raise the whole mash back to 73 C at the end to ensure its conversion. This means two mashings. But, it would probably result in a drier beer, and improved efficiency, but at the cost of twice the time (and energy).

This leads me to think that perhaps you could do a double mash – just mash half of your grain in a multi-step, but don’t raise the heat and mash out. Instead then mix in the remaining grain and water, and start over. This would mean that the beta-amylase from the second mashing would get at the long-chain sugars from the first first; and there would be a lot of alpha-amylase around from the first mashing to ensure complete conversion in the second mashing. The advantage to this method is that you can do it all in one mash-kettle, and you don’t have to mess around draining off half the mash then adding it back in (hot, sugary water is kind of scary to handle).

I think the broader question is whether this is even worth it. These days my mashing method involves:

  1. Using half the water (bringing the mash thickness closer to what non-BIAB home-brewers use – results in improved efficiency and makes raising the temperature of the mash during intermediate steps easier),
  2. Doing a three-step process (the 63 – 67 – 70 C) with 20 minutes at each rest,
  3. Then adding in the rest of the water (at 52 C: temperature of the water that comes out of the hot water tap),
  4. Which drops the temperature back down to around 63 C, then raising the heat to 75 C for mash-out.

This method has been giving me brew-house efficiencies around 80% consistently, and it does not take much longer than my usual mashing (the time it takes to heat up between steps is around 5 minutes, and the final heating takes around 20 minutes). Is it worth doubling my mashing time to get efficiency up to 83 – 84 %? Maybe on a commercial scale, but for me, the extra points of efficiency are not worth it.

As well, you would probably end up with beer with no character or flavour.

The final thing I want to point out is that alpha-amylase on its own is a very effective enzyme at producing simple sugars. Think about it – animals, including humans, get by with only alpha-amylase. Many ‘beers’ (e.g. chicha) in traditional economies are made with grain mashed using human saliva. If given enough time and the right conditions, alpha-amylase can convert starch into simple-chain sugars. It’s just faster utilizing beta-amylase.


  1. Thanks for this verbose answer! I suppose you are right in claiming that my method is not very efficient. Your answer leads me to one other remark: you use half the water, which indeed is more efficient. But in order to get a drier beer, a *thinner* mash is better. And, according to a recent and thorough experiment on the homebrewers-forum in the Netherlands, a thinner mash with no sparging leads to a very minor loss of efficiency.
    Maybe you could even improve your champagne of beers by using a thin mash?

    Comment by Sjoerd — March 12, 2009 @ 8:03 pm | Reply

  2. Just so we’re clear, I have already brewed the ‘champagne’, and don’t plan to do it again – it’s a bit of a hassle. Unless I really, really like it. When I brewed the ‘champagne’ I did not use half of the water – I used all of it at once, so it was a thin mash. In fact it was a VERY thin mash because so much of the gravity came from cane sugar, which I only added later, during the boil. But explain why the thickness of the mash would affect the fermentability of the wort.
    I’m very interested in your “recent and thorough experiment” regarding the efficiency of thin mashes. Tell me more! My own very un-thorough, ‘gut feeling’ experiment is that I get better performance when I use half the water. Remember, that I end up adding the rest of the water at the end of the mash, when the grain is still in the tun, so I do get a ‘thin’ mash at the end. I drain my bag of spent grain only after adding the rest of the water.

    Comment by iwouldntlivethere — March 13, 2009 @ 4:06 am | Reply

  3. And what did you think of the repeated mash method?

    Comment by iwouldntlivethere — March 13, 2009 @ 4:07 am | Reply

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