Mash Time Experiment

[thumbsucker]

I pro brewer I known has mentioned in passing a few times that modern malts convert super fast and that he limit his mashes at the distillery to 30 minutes.


To test his statement today I brewed a ESB.

I added 12kg of malt to 45 litres of water with a mash temp of 68c I then started to take samples:

After 25 minutes the refractometer read 1070.
After 50 minutes the refractometer read 1070.
After 90 minutes the refractometer read 1070.

My testing confirms his experience.

So why do people always say mash for 60 to 90 minutes? A matter of tradition, habit what do people think?

 

[mtb]

The long mash is to do with flavour extraction, not starch conversion. It's generally accepted that 30min (ish) is sufficient for conversion.

 

[manticle]

There is more than one enzyme responsible for starch conversion and more than one type of sugar the starch is converted into.

I do a 30 min mash for one type of beer at around 70 deg but most others are longer.

You say pro brewer but also distillery. Is it beer or whisky they are making from their mash?

 

[MHB]

Just because starch has been chopped up small enough to be soluble doesn't mean its as fermentable as it's going to get if you wait longer. Nor that it will give the flavour profile we are looking for in the beer we are making.
I have to say I'm a little surprised at a pro-distiller only doing 30 minute mashes, typically wash mashes are rather cooler than beer mashes and aim to make as much fermentable sugar as they can, so are often slower, or have a bunch of exogenous amylase tipped in (often Beta Amylase).

Braukaiser had a bit of a look at just this question in one of his experiments, always worth reading his work.

Mark

 

[Mardoo]

FWIW, here's what the Brulisophy guy has to say about this. Not everyone agrees with his results, but there's usually some good stuff to spur thinking.

http://brulosophy.com/2014/09/01/does-mash-length-matter-exbeeriment-results/

 

[Matplat]

Interesting reading.... I guess it's arguable that even though fermentability of the wort does increase, the gain achieved isn't worth it compared to the extra time/cost imposed. A pro brewer could do a second mash in the extra time taken, which would be far more beneficial financially.

On a side note, if you achieve a negative iodine test after 40 mins, how are you able to extract any more sugar after that point?

 

[MHB]

Think about the implications of the wort under attenuating!
If your beer is too sweet or the ferment stalls at 1.020 I'm sure you would be on here blaming the yeast or the temperature... in fact anything other than the brewer who made a defective wort.

The world is full of "Pro Brewer" who really know what they are doing, lots of them have uni qualifications in brewing. Before we decide that they are too stupid to work out the cost benefit of mash time, it would be a good idea to get our heads around what really happens and how it affects our beer.
Mark

 

[manticle]

Interesting reading.... I guess it's arguable that even though fermentability of the wort does increase, the gain achieved isn't worth it compared to the extra time/cost imposed. A pro brewer could do a second mash in the extra time taken, which would be far more beneficial financially.

On a side note, if you achieve a negative iodine test after 40 mins, how are you able to extract any more sugar after that point?

What's 'sugar' in this context?

Shortening mash time and mashing at a higher temperature (alpha amylase is the faster of the two conversion enzymes) is a very legitimate way of deliberately making a dextrinous wort.
Should you wish for a less dextrinous wort (which in many cases is likely) then your processes will likely include a mash that is both longer and lower in temperature.

Starch conversion is a function of a number of variables - temperature, time and pH are 3 major ones. I would absolutely recommend playing around with time and temperature to get a feel for what they do -accepting a default 60 mins without understanding why doesn't help you learn. However there is a point that goes way beyond shaving 20 mins off a brew day. If that's the only goal, try extract brewing*.

And leave brulosophy in the entertainment section.

* Not intended as a derogatory statement about extract - just purely that it is quicker due to the mashing aspect being already taken care of.

 

[Lyrebird_Cycles]

A pro brewer could do a second mash in the extra time taken, which would be far more beneficial financially.

On a side note, if you achieve a negative iodine test after 40 mins, how are you able to extract any more sugar after that point?

No, lautering / mash filtration is generally the pinchpoint in a real brewery. One performance metric for a standard brewhouse is lauter time x extract efficiency: as one goes up the other goes down.

Iodine indicates that you no longer have any starch chains long enough to form a chromophore. It is perfectly possible to have an iodine negative starch breakdown product which has no fermentable sugars: maltodextrin is an example.

I would also point out that the experiments talked about above are all done with brewhouse efficiencies under 90%: that would be completely unacceptable in a real brewery. With more typical efficiencies (>97%) the deficits in a short mash will become proportionally larger. A 1% efficiency loss is a big deal in a brewery: I spent all of yesterday in a local brewery doing some experimental work, at the end of the day the brewers and I were chatting over a beer, they were discussing ways of dealing with a newly identified loss in the packaging process which came to a little under 1%: the cost involved was very large, probably enough to pay for a new filler.

 

[hoppinmad]

I am reminded of a thread posted some time ago on here where many people were demonstrating that you can actually make some awesome beers using a short mash and boil. BribieG himself stated using a 30 minute mash and 30 minute boil created the best English bitter he had ever made
http://aussiehomebrewer.com/topic/76190-10-minute-ipas-are-good-for-school-night-brewing/page-3

 

[MHB]

Yes you can make "good" beer with shorter mash times (well some styles) but there will be a price, same with short boils, under/over pitching yeast, water quality...
There is always a tradeoff!
Mark

 

[Matplat]

So I think there is a gap in my understanding here, by sugar, I meant 'that which will cause the specific gravity to rise' I have assumed that starch that is in solution does not, correct? Do different sugars affect the specific gravity differently? The braukaiser experiment shows that the time factor, for a given mash temperature, doesn't significantly impact the fermentability of the wort, nor does it significantly increase the volume of sugar extracted.

Perhaps my argument only comes in to play when the mash tun is operating round the clock. If there are more gains to be gotten by correct lautering, and you are pushed for time with the mashing process, it is seemingly more productive to perform multiple shorter mashes, albeit at a [slightly] lower efficiency.

If the brewery has plenty of time to complete the mashing process, then obviously it would perform the longer mash to maximise efficiency.

 

[manticle]

The point is that the hydrometer won't distinguish between types of sugar.

There is more than one type in beer, some more fermentable than others so the type and amount has a very real effect on attenuation, mouthfeel, flavour, etc.

Maltose is not sucrose is not dextrose is not galactose.

 

[MHB]

If you have a look at the time scale in the Braukaiser experiment you will see that het is pushing out to 160 minutes and his first data point is 40 minutes.
I strongly suspect if someone did the same experiment with samples taken at 10,20,30... minutes you would see a lot of change in both the gravity and fermentability, Kai surely knows this and didn't even bother taking samples that soon in the mash.

I ones heard there are something like 26 million known sugars, if any of them are in solution it/they will affect the gravity, as will salts, alcohols, proteins... if fact anything in solution will affect the SG, each one would have a unique effect as a factor of concentration (you can get a saccharometer and a salinometer, they look the same (are the same) apart from the scale).
If we look at the make up of a "standard" commercial wort, 8% minerals and other bits, 4% protein, 5% pentosans and glucans, 20% non fermentable dextrins, the balance (63%) being 40% maltose, 8% maltotriose and 15% simple sugars. If you start playing around with the mash time/temp/pH/Ca.. too much that balance can go out the window pretty quickly.

As for the economics of mash time and brewery throughput, that's something that is a razor edge balance, the old big two in Australia used to take opposite approaches, one went for more low efficiency mashes, the other fewer higher efficiency mashes a day. Funny enough the cost in $/L was within a mick hair of being the same

Mark

 

[Lyrebird_Cycles]

I have assumed that starch that is in solution does not, correct? Do different sugars affect the specific gravity differently?

Starch in solution contributes to SG.

Different sugars do affect the SG differently but these differences are small and can be safely ignored: a 10% solution of sucrose (10 Brix) has a density of 1.0381 whilst glucose and maltose are both 1.0385. I cannot find a good answer for maltodextrin or starch but the info I can find indicates they are very close.

I measured a 20% solution of maltodextrin and got a value of 19.2 Brix, which is consistent with typical powdered maltodextrin having 4 - 5% water content.

 

[Gelding]

I ones heard there are something like 26 million known sugars

And each one of them has a name ending in 'ose' ?

I once knew a chemistry PHd student who couldn't quite discern the structure of a new sugar he'd discovered, so he named it godnose.

 

[MHB]

You probably wont find an answer as they are Maltodextrins (3-17 Glucose Units) and Starches (around 20-50 GU, maybe more), the plural being the problem, lots of different molecules in each family and each would be unique, if not too different from each other.

 

[Lyrebird_Cycles]

I was looking for values for particular maltodextrins like the common 10, 15 and 20 DE, the standard "back of envelope" calculation is that DE x DP = 120 (obviously the calculation fails for the monomer but it's usable from the dimer up).

The stuff I've got is 15 DE (I think*) so it has an average DP between 6 and 7. The info I have is that the spread of DP is fairly narrow, usually >80% is within +/-2 units of the average.





* It came from Grain and Grape and they list it as 15% fermentable which is completely wrong. I think they've merely misunderstood what 15 DE means.

 

[MHB]

What do you mean by DP?
DE, Dextrose Equivalent, the standard measure of fermentability, as I understand it DE 15 would be 15% as fermentable as dextrose (anhydrous) and the number is measured with a redox meter.
Mark

 

[manticle]

DP = degree of polymerisation, I'm presuming.