Mash Question

[Pelikan]

I've been told that the bulk of mash conversion occurs within the first ten minutes. Any thoughts on this? Why 60 minutes (as opposed to 30, 45, 120, etc)?

Just curious, for curiosity's sake.

 

[HotbreakHotel]

Some people only hold their mash for 20-30 minutes.

I understand holding the mash longer breaks down the grain more and makes it more fermentable. I just read (heard?) (can't remember where) that if you hold the mash for two to three hours it will break it down even more and make it even more fermentable.

 

[Got Trub?]

Modern modified malts will quickly convert most of the starch in the mash well before 60 minutes - assuming the bulk of the malt is base malt. The more non-base malt added the more time you will need. You will continue to get some conversion and improve your efficiency by longer mash times but it is dwindling returns, you will also create a more fermentable wort which may or may not be desireable. Mash temperature also has a role, I mash for 90 minutes when doing cooler mash temps like 146-148F. The main thing is be consistent so your efficiency and fermentability is reproducible from batch to batch.

GT

 

[david_42]

60 minutes will result in full conversion for just about any grain bill and temperature (below 149F you need more time for full gelatinization). If you do starch testing, shorter mashes are in your future.

 

[SpanishCastleAle]

When I do decoctions I want the decoction to convert as fast as possible and I immediately pull the decoction as soon as I hit the low rest temp (which is below the real 'conversion' temps...like a 122 F protein rest). I test it at 10 minutes and it's usually converted or close enough to continue with the boil. This is around 158 F though. Lower temps mean slower conversion.

The mash doesn't stop converting at 168 or 170 (typical mash out temps). The alpha-amylase is still converting and doing it fast at that temp...the sugars converted may not be fermentable...but available starches are still getting broken down to complex, unfermentable sugars.

The main thing is be consistent so your efficiency and fermentability is reproducible from batch to batch.

I agree. IMO, you need to be able to manipulate the fermentability of your brews so that they finish where they're supposed to finish (other factors come into play too)...but you need to be able to do that while maintaining a consistent (or at least predictable) efficiency.