Diastatic power

[Mr. P]

Hi!

I have brewed a strong ale, and because of my limited mashing capacity, I had to replace some of the base malts with dry extract. In the process, I was wondering whether I had enough diastatic power left to convert the dark malts.

Will it be possible to implement a feature, which gives a warning, if there isn’t enough diastatic power?

(Thanks for a fantastic program! Keep up the good work - it's appreciated!)

[BeerSmith]

Hi,
  It depends on how much and what types of grain you are mashing.  For partial mashes, usually a few pounds of pale malt provide enough to do the conversion.  In general I would recommend at least a few pounds of pale malt.

  As a separate question, yes I suppose it is possible to incorporate an estimate of diastatic for the overall batch.  I probably need to do a bit of research to find the appropriate formula.  However, it does become a challenge defining a true threshold as many beer styles (quite a few using wheat for example) have relatively low numbers.  Once needs to also consider the size of mash vice size of whole batch.

  However, I will look into it...it is an interesting suggestion.

Thanks,
Brad

[Mr. P]

On this page http://en.wikipedia.org/wiki/Diastatic_power I found this information:

A malt with enough power to self-convert has a diastatic power near 35 °Lintner

Is it too simple an approach just to calculate a weighted average of the diastatic power and check if the number is greater then 35?

An example:

Pale Malt: 2,1 kg * 100 °Lintner = 210 kg*°Lintner
Munich II: 1,9 kg * 25 °Lintner = 47,5 kg*°Lintner
Carafa I: 0,7 kg * 0 °Lintner = 0 kg*°Lintner
Special B: 0,70 kg * 120 °Lintner = 84 kg*°Lintner
Caramel/Crystal Malt - 60L: 0,60 kg * 0 °Lintner = 0 kg*°Lintner

Weighted average = (210+47,5+0+84+0)/(2,1+1,9+0,7+0,7+0,6) = 57 °Lintner > 35 °Lintner, i.e. sufficient diastatic power.

By the way: In BeerSmith, the diastatic power of Special B is set to 120 °Lintner. That seems way to high for such a dark malt. Is 120 °Lintner the correct value for Special B?

[BeerSmith]

Thanks!
  I will run some sample calculations on some recipes to see how this turns out.  It would be a nice addition especially for partial mash brewers.

  I believe the special B number is in error - as it sounds way too high but I will check it against some paper references to verify before correcting it in the updates queue.

Brad 

[Dr A]

Can I bump this Brad?

I think a tool for estimating the diastatic power of a mash would be really, really useful, especially when doing a partial mash or with an extra-high quantity of speciality grains.  As far as I know, you need a DP for the whole mash greater than 35-40 Lintner for full conversion and a little warning would be useful if the recipe goes astray. It would save me making a beer that never quite gets to the FG I expected!

I realise that slight differences in malts would make this not wholly scientific, but even as a ball-park figure in the margin next to the FG estimate, it would be great to have a little warning if the DP average drops below 35 Lintner.

All the best, and keep up the excellent work

Andy

[MaltLicker]

I believe Special B malt is zero Lintner.  Most crystal malts are kilned with significant levels of moisture which nukes the enzymes. 

I would think such a formula could actually ignore crystal grains, however, because they don't need converting.  The maltster did that for us in the kilning and roasting processes. 

If I recall correctly, there are a handful of grains that are enzyme-dead themselves, but need mashing to convert some of their remaining starches.  So the trick is to know those grains and use caution when pairing those grains with things like Munich that have just enough to convert themselves.  As long as you have a pound of two-row or pilsner in a partial mash I would think you'd generally be fine.