Saccharification Time

[micblair]

I've been following the conversion of my mash with a 2% w/v solution of Lugol's iodine, and I'm amazed by how fast saccharification takes place. On my system, 20 minutes at 65C is negative by the starch-iodine test. Given that amylose has a turn for every six glucose residues, the wort at this point is by no means highly fermentable, as at maltopentaose would be the longest dextrin present (along with a statistical mixture of glucose, maltose, maltotriose etc.). So I'm curious to how long you 'actually' need? Certainly mashed for 45 mins, and produce wort with a similar fermentability as a 60 minute mash. I know a lot of users use extended mashes, but is this predicated on anything other than "this is always the way I've done it"?

 

[Helles]

I mash for 2 hrs minimum any less and i get less %eff
Havent done an iodine test
But %eff is being lost so extended mash from 60 min to 90 min to 120 min
As brew length changed from 50 lt to 80 lt to 115 lt

 

[Ducatiboy stu]

Many brewers prob dont realise that saccharifation occurs rather quickly which is why mash temp is very critical within the first 15mins..

The use of xtals and other non modified grains is prob the reason for a long mash so as to extract the most from them....but then again 60mins is a good amount of time to sit back and enjoy a frw beers

 

[black_labb]

I have found the length of time makes a big difference to fermentability. When i started step mashing I would ramp to 72 towards the end of the mash and leave it there for a while. Even with high mash temps I was getting very low FG. When I included the ramp to 72 in the 60 minutes I had the expected FG readings. While the starches are not going to be present after 20 minutes you will not have given the enzymes much time to break down the long chain sugars and it would be less fermentable than a longer mash.

 

[manticle]

If I'm not stuffing up something really obvious, doesn't an iodine test simply tell you if starch is present? It won't tell you which chain length sugars are present so longer simply gives beta a chance to keep chopping up dextrins (finitely of course).
You could convert starch to dextrins in 15-20 minutes at high temps but another 30-60 mins will give beta time to work to make more fermentable wort.

Other factors involved like mash/wort pH too.

 

[GuyQLD]

If I'm not stuffing up something really obvious, doesn't an iodine test simply tell you if starch is present? It won't tell you which chain length sugars are present so longer simply gives beta a chance to keep chopping up dextrins (finitely of course).
You could convert starch to dextrins in 15-20 minutes at high temps but another 30-60 mins will give beta time to work to make more fermentable wort.

Other factors involved like mash/wort pH too.

Not really adding anything other than verifying that even when Manticle isn't sure - chances are he's probably right (as he is in this case)

 

[micblair]

Nice bromance going on above. But yes that's right manticle, it's a qualitative test. But as the OP says, a hexomer of glucose should test positive, whilst a pentomer will not as there won't be sufficient helicity for a triodide - starch complex to form. Beta amylase is probably best exploited at lower temp so mashing high then expecting fermentability might be a big ask. But given amylose and amylopectin are dextrose polymers containing anywhere from a few hundred to few hundred thousand units, surely dealing with maltohex/pent/tetraose etc. would be a snack after the bulk of the hydrolysis has taken place? In other words how much extra time is really necessary?

 

[manticle]

65 is right at the tail end of the optimum range for beta. I'd be interested to know if you got similar results mashing at 60. My understanding is that alpha when favoured works quicker than beta when favoured.
To answer your question though - in many cases it would simply be a matter of 'this is how I've always done it. You're interested in a very specific detail that not everyone will question.

Currently reading the de clerck section on mashing to see if the answer is in there. Interested to note that iodine does actually have some distinction between polymer types. Purple brown to brown/violet to none. Hard for a layman to interpret between the browns, purples and violets I guess.

Be interested in conversion times and fermentable extract for 60, 65, 70 at pH 5.4 and 5.8 (6 mashes all up) if you could be bothered.

Pretty sure that if beta is not denatured, it will cut dextrins up so mashing high then low can work.

 

[Ducatiboy stu]

60mins...yeah ...thats is the established method

Has anyone made a beer from a 20min mash to see what the difference would be...

 

[GuyQLD]

http://braukaiser.com/wiki/index.php?title=Effects_of_mash_parameters_on_fermentability_and_efficiency_in_single_infusion_mashing

This may be relevant, its missing all the fancy words but he does do a number of iodine tests vs time.

 

[manticle]

60mins...yeah ...thats is the established method
Has anyone made a beer from a 20min mash to see what the difference would be...

I mash all my milds for 30 mins at 70 but I've never tried that beer at 60 as a point of comparison. Result is as expected - fuller body, higher fg.