Longer Mash Time = Higher Efficiency?

[drsmurto]

Brewed mach 2 of Warrens 'Just a tickle' Dark Mild yesterday.

Doughed in too hot (71) so added cold water. Checked temp. 66. #$^%^^% Thankfully i always have a kettle full waiting so 2L of boiling H2O and i got it to 68 (with a 2nd kettle of boiling water....) and decided that was close enough to my desired 69C. Water/grain ratio was near on 4 tho. (Am normally around 2.5ish)

Got sidetracked and decided that since all didnt go well i would leave it and deal with it after dropping sis off. 4 hours later i got back to it and mashed out etc.

Efficiency went up to 80 from my normal (and consistent) 70%.

Is this to be expected? I realise a 4 hour mash is not normal but what if i did a 90 or 120 min mash would i expect to see an increase in efficiency? Is this telling me i am getting very slow conversion? Or did a very thin mash help out?

The recipe is - HERE

Any thoughts appreciated.

Cheers
DrSmurto

 

[Screwtop]

From Experience: Longer Sparge = Higher Eff, so I would guess the two would be related, water and grain together longer.

Also would be interested to know what Apparent Attenuation you get from the higher L/Kg mash, have made a few at 3.5 - 4L/Kg and they have achieved higher attenuation using a variety of yeasts.

Cheers,

Screwy

 

[Fatgodzilla]

From Experience: Longer Sparge = Higher Eff, so I would guess the two would be related, water and grain together longer.

Also would be interested to know what Apparent Attenuation you get from the higher L/Kg mash, have made a few at 3.5 - 4L/Kg and they have achieved higher attenuation using a variety of yeasts.

Cheers,

Screwy

Never thought of this before, but do we mash for 60min / 90 min simply to allow us to brew in a day ? What would happen if we mashed overnight - say 8 hours at 68C - is this likely to have any detrimental effects on either efficiency or quality ?

 

[drsmurto]

From Experience: Longer Sparge = Higher Eff, so I would guess the two would be related, water and grain together longer.

Also would be interested to know what Apparent Attenuation you get from the higher L/Kg mash, have made a few at 3.5 - 4L/Kg and they have achieved higher attenuation using a variety of yeasts.

Cheers,

Screwy

Higher attenuation? Bugger! Last time i mashed at 69-70C and using the 1187 Ringwood yeast went from 1.040 to 1.020. Ended up at 1.044 this time so was hoping it wouldnt go below 1.020 again. Tis fun keeping the bugger from going to sleep tho! Daily rousings seem to do the trick.

 

[Cortez The Killer]

From the literature I have read

As we have well modified base malts most of the conversion is done in the first 15-20 mins

Here is a link to a thread on point

http://www.aussiehomebrewer.com/forum/inde...c=18036&hl=

Cheers

 

[therook]

Never thought of this before, but do we mash for 60min / 90 min simply to allow us to brew in a day ? What would happen if we mashed overnight - say 8 hours at 68C - is this likely to have any detrimental effects on either efficiency or quality ?

Here you go Fats

Overnight mash

Rook

 

[Adamt]

You can probably attribute the extra efficiency to the smaller grain bill of a mild, rather then the extra time for conversion.

You're sparging with more water per mass of grain with a small grain bill and so you leave less sugar behind.

I jumped 10% efficiency yesterday brewing a "weaker" batch, I only mashed for 45 minutes too, now that I think about it.

 

[drsmurto]

You can probably attribute the extra efficiency to the smaller grain bill of a mild, rather then the extra time for conversion.

You're sparging with more water per mass of grain with a small grain bill and so you leave less sugar behind.

I jumped 10% efficiency yesterday brewing a "weaker" batch, I only mashed for 45 minutes too, now that I think about it.

Adam, your 'weak' beers are ~6%, this should be around 3%! :lol:

This is the 2nd time doing this beer and last time efficiency was spot on 70%. 60 min mash.

 

[shonky]

Hi,

According to Briggs ( Brewing: Science and Practice) longer mash times will increase extract, allbeit not by much. Maybe more significant, from his figures is the effect on FAN levels whereby more nitrogen (=good for yeast health) is extracted from a longer mash and also increases in fermentability.

Some of his stats around this include:

For 30 mins 60mins 120 mins 180mins
%ext 60c mash 53.4 57.2 60.7 62.2
%ext 65c mash 62.2 62.8 63.6 63.6
%ext 70c mash 62.5 62.9 63.4 63.6

Tot% Nitr 65c mash 30.7 32.9 33.7 34.6

Fermentability 65c 46.6 48.5 50.7 51.7

I suppose you can draw from these that it makes b*gger all difference, especialyl as homebrewers where we don't (tend) to use many adjuncts. Fermentability might be of interest though to those doing overnight mashes as you could expect a dryer beer based on these figures.

Cheers, assume it's Ok to quote a few figures in the interest of good beer h34r:

 

[Fatgodzilla]

Here you go Fats

Overnight mash

Rook

Thanks Rook - very interesting thread which reinforces suitablity of overnight mashing if needed. Well worth the reading.

 

[Thirsty Boy]

Just speculating but -


A long mash time wouldn't change a hell of a lot about your fermentability profile, if the mash temp was reasonably high. At say your starting temp of 68C, by the time you got to your standard 60mins worth of mashing time, most of your Beta Amalayse enzymes will have been de-natured and wont be doing much at all, the Alpha Amalayse will still be chugging along just fine, but will probably have done most of what they can by then anyway. The extra time will most likely just make sure that everything that can get done, is done, a bit of extra hydration and maybe a bit more starch accessed, dissolved and converted, giving a little bit more extract - maybe.

If on the other hand it was a lower temp mash, starting at maybe 64 or 65C - then there would be some action. The beta amalayse would last much much longer and be even less likely to become de-natured as teh mash cooled down over time. The the extra time for the betas to work plus the possible extra access to any starch that takes a long time to dissolve, means that you would get a really very fermentable wort.

The long low temperature mash is exactly the way a number of commercial "low carb" beers are brewed - hte best example probably being Bud Light where they have a 4hr low temp mash to knock out most of the dextrins.

Its nothing that you don't get with a normal length mash - ie high temp = less fermentable, low temp = more fermentable - its just that the effect is going to be pretty severely magnified because of the rates at which the enzymes denature at the higher and lower temps. A degree or two difference in mash temp is going to make a lot more difference to your profile with a "long" mash time.

Or thats how it seems it would go to me

Thirsty

 

[Ross]

As adamt explained - the smaller grain bill off a low alcohol beer will increase your efficiency.
Mine jumps from 80 to 90+ whenever i do a low alcohol beer, & conversly a large grain bill has the opposite effect.
I'd suggest the previous low alcohol brew you did must have had something go wrong, as your results this time are normal.

cheers Ross

 

[Darren]

Hey Dr S,


Not sure if this was mentioned but certainly your high water:grain ratio will increase extraction. It is an equilibrium thing. The more liquid present, the more sugar that can be extracted from the grain before the equilibrium is reached (ie same amount of sugar in the grain as in the liquid).

Not sure if this makes sense? To put it another way, have you noticed that it is impossible to get first runnings over 1.085 no matter how big your grain bill is? This must represent the maximum amount of sugar extracted/dissolved prior to reaching equilibrium.

If you add more water and less grain the equilibrium is forced in favour of the water (in excess) therefore more sugar is extracted prior to sparging.

cheers

Darren

 

[Cortez The Killer]

Following on from this thread

Would 2 sparges help with extraction?

As the amount of sugars remaining in the water held by the grain would be less after the second sparge % wise

Or is it much of a muchness?

Cheers

 

[drsmurto]

Cheers for all the responses.

Did think it funny i still got 70% the first time i made the mild when i get 70% making beers up to 5-5.5%.

So hopefully this version is even better

I have tried splitting sparge volumes in 2. Thought rinsing twice would extract more but didnt notice a difference and it took longer.

i did think about the solubility of sugars in water. Was wondering why people choose the l/kg ratios they do but thats another thread entirely and i recall reading something about that on here before.

A quick look thru my last 10 beers (all single infusion + mash out) and the L/kg ratio is all over the shop! Ranges from 2.3-3. And i have the gall to call myself a scientist Will lock it in for the next few beers and see how that goes. Or do people change this ratio depending on OG, mash temp etc?

25 AGs in and i still feel like a noob!

Cheers
DrSmurto

 

[SJW]

Just a note, I brewed a Stout the other day and mashed at 69 deg C and the OG was 1.054, I fermented with Nottingham and it ended up FG 1.020.

 

[drsmurto]

FG of the mild was 1.017 - last time it was 1.020 so the extra long mash seems to have aided the attenuation.

Continuing this discussion, i have been doing a little experiment with L/kg and mash times, i locked in both.

So for the last 3 beers, all now in primary, i used 2.7L/kg and mashed for 90 mins.

In all 3 cases my efficiency was 75% when it is normally a reliable 70%. Nothing else has changed AFAIK.

Its got me thinking that maybe in the past i was not actually getting full conversion and i have never tested for this.

Quietly impressed with myself!

Next test is to get my grain crushed on someone else's mill to see how much better it is than my marga

Cheers
DrSmurto

 

[rich_lamb]

Yeah, I hate that all-over-the-show temperature profile you get when you try to adjust!

The extra efficiency can also be partially explained by the temperature profile in the mash - Thirsty was hinting at this, though I don't believe the B-amylase is significantly "denatured" at the higher mash temps.

Mash tuns aint mash tuns, and most of us quote a mash temp as though it's completely constant over 60-90 minutes, which it rarely is. And the point in time you initially measure it is significant, since it's changing fastest just after dough-in.
In theory, if you start out with a high mash temp and this slides down a couple or more degrees into the low-mid 60's over your mash you can create much more fermentable wort and get better extraction.

I can't speak from experience tho - my efficiency is normally about 64%. I know why - I have a small tun and only sparge once, so my final runnings are typically about 1.029. And yes, I would get a massive bump in efficiency if I continued to sparge, but can't do that till my new kettle's built

I'm with the "dextrin hounds", and I would avoid a longer mash if only to prevent any increase in fermentability.

 

[mika]

Whenever I've mashed for longer than 60minutes, up to 90mins in some cases, I've never noticed a difference in efficiency. That is to say, not more than the 2-3% swing that my system seems to have.
I haven't done it consistently enough to notice a difference in attenuation, I've always mashed at 3L/kg and vary my mash temp to get the attenuation I want.
Interesting though as Dr Smurto's experiences go against the commonly accepted ideal of the mash being mostly converted after 20mins.

 

[drsmurto]

I get about a 2C drop over the course of 90 mins. I preheat the tun (55L esky) and put a piece of rubber matting over the mash as there is a huge air gap between mash and top of tun. I wrap the whole thing in a sleeping bag.

Have done lots of reading about all the different effects of the 100s, maybe 1000s of variables when it comes to AG. Wasnt sure that an extra 30 mins would do much but i did notice that in the past the 2nd runnings were still quite strong (up to 1.024). The last 3 have been around 1.012. Maybe i need to do 2 identical batches with a 60 and 90 min mash and test for conversion at set times.....

I guess if i dont crush as fine as others (using a modified Marga) it may take longer to convert..... as it will take longer for the enzymes to get to the starches. We could get into a discussion on molecular dynamics (Braufraus HWMBO could help us out) to try to explain this but i wont.

As i eluded to earlier, is there are hard and fast rule when it comes to L/kg ratio in relation to mash temp, fermentability, style of beer etc?