Stout - Mashing Time

[Ross]

Hi guys,

Just mashing an Imperial style stout as we speak - I have researched a fair bit, but there seems to be a big varience in mash times suggested (at the same temps) for recipes that seem fairly similar - IE 90 mins to 150 mins...

I was planning on 90 mins, but am I better to mash longer? What are the reasons behind the much longer mash?

P.S. I'm cold steeping the speciallty grains as I don't have the means to check my PH yet...

 

[SJW]

I do a lot of dark AG beers including stouts and first of all I dont worry about mash ph levels, they wont be a problem with a big dark beer like that, so I just mash all the grains together. And for that big beer taste i mashed my last stout at 71 deg C for 90min's and i also make a habit now of using 500g of Uncle Tobys "QUICK" Oats in the mash also. Make sure they are QUICK OATS. But I think u will find with the high quality grain we use in Aust. most of the conversion will be done in the first 30 to 45 min's.
Anyway that just what i do, but i am sure someone else can give u some technical data on the subject.

stephen

 

[jayse]

Hi Ross,
I don't think there will be any benitfit in mashing for 2.5 hours after the 90mins everything should have reached completion already and if not it would not be likely to have any enzymes left to do anything anyway.
It has been discovered that very little or indeed none at all of the enzymes used for the saccaride rest will still be active after 90mins at normal mashing temps.

So with that you can conclude that a longer mash time is of no value.


Over the hills and far away.
Jayse

 

[Gulf Brewery]

Hi guys,

I was planning on 90 mins, but am I better to mash longer? What are the reasons behind the much longer mash?

P.S. I'm cold steeping the speciallty grains as I don't have the means to check my PH yet...

[post="54395"][/post]​

Ross
Conversion of the starches should occur in 90 minutes, if it doesn't happen by then, its not likely to in 150 minutes. The enzymes will start to be severely denatured by then,

I would be tempted to use some of the dark grains in your mash as it will drop the mash pH slightly and allow for better conversion.

Cheers
Pedro

 

[warrenlw63]

I've been finding lately if you're using local malts (Joe White's) you can get away with complete conversion at 60 mins.

I'd be pushing the limit here but if rushed you could almost get away with 45 mins. at higher mashing temps.

I used to mash for 90 mins and I'm inclined to think that this still is the safest way.

However if you're like me and you're often pressed for time... taking 30 mins. off the mashing time gets you three-quarters of the way through the sparge, (which takes me 45 mins to obtain 40 litres).

Wouldn't do this with imported malts. (Example Fawcett's) I still mash for 90 mins.

(Hey Wes! This is your field of expertise )

Warren -

 

[Gulf Brewery]

warrenlw63

Good point about the time. I should have said in my post, that with recirculation (HERMS), I can get conversion in 20 minutes max with most malts. I was only really commenting on the time Ross was looking at.

Cheers
Pedro

 

[Ross]

Thanks guys,

Looks like 90 mins & 67c then... 15 mins to wait.

SJW - I added 500gms of "Farmland" rolled oats, trust they're ok?

To late to add the dark grains, I usually just add the grains strained from the liquid to the mash tun just before adding sparge water, seems to work well...

 

[warrenlw63]

warrenlw63

I can get conversion in 20 minutes max with most malts. I was only really commenting on the time Ross was looking at.

[post="54412"][/post]​

20 mins. That's pretty impressive stuff. With modern malts these days 90 min. mashes are more for people with lots of time on their hands.

All that aside you still hear of people mashing in at night, going to bed and doing the sparge the next morning to better factor their time. Not sure of the overall results but no harm seems to come of it.

Be interesting to compare identical beers mashed at say 60-90mins and overnight.

IIRC some brewers laid claim that overnight mashes led to a more attenuated beer. Find it difficult to believe though.

Warren -

 

[warrenlw63]

Oh. I forgot to mention.

Rolled oats are fine Ross. Just bear in mind that 500g could lead to a slightly sticky (even stuck) mash. I'd cut them in half personally. YMMV

Warren -

 

[Ross]

Warren,

I've got 250 gms of puffed wheat in as well so should help - Also my batch sparging is set up for the really fine milling my HBS unfortunately provides... So should be fine - thanks again for the tips....

 

[Trough Lolly]

Ross,
My water here in Canberra is pretty soft, so it is ideal for pale ales and pils etc but not so perfect for dark ales and stouts. When I make my dry stouts, I usually mash for 60 mins and add a teaspoon of gypsum to the mashtun before dough-in.

If conversion isn't finished by 60 mins, then it never will! I'd rather spend the remaining 30 mins on a more efficient sparge. I have mashed the exact same brew for 60 and then 90 mins and had bugger all difference in the product other than taking half an hour longer to reach primary!

Cheers,
TL

 

[Tony M]

I've been finding lately if you're using local malts (Joe White's) you can get away with complete conversion at 60 mins.


Warren -

[post="54409"][/post]​

I did a mash with AMC and Hoepfner malt a couple of days ago and at 65 minutes the iodine test was negative so commenced mashout. 20 minutes later, I happened to glance at my iodine test sample and it had telltale black streaks running right thru it. So maybe more than 60 minutes is needed for peace of mind.

 

[Ross]

TL,

I'm on tank water - I added 1 tsp calcium carbonate to the mash + added 1 tsp of calcium Sulphate & half tsp magnesium sulphate to the boil - hope this sounds right...

 

[SJW]

Oh. I forgot to mention.

Rolled oats are fine Ross. Just bear in mind that 500g could lead to a slightly sticky (even stuck) mash. I'd cut them in half personally. YMMV

Warren -

In my Milk stout I used 1kg of Quick Oat's + 500g of Flaked Barley and in ran like a dream (no stuck sparge) I think unless your using a mash setup with a very deep bed you should never get a stuck sparge, believe me i've tried. If you used oats that had no been rolled they should be pre mashed (I am shure there is a better word than pre-mashed) but Quick Oats are fine.

STEPHEN

 

[Trough Lolly]

TL,
I'm on tank water - I added 1 tsp calcium carbonate to the mash + added 1 tsp of calcium Sulphate & half tsp magnesium sulphate to the boil - hope this sounds right...

[post="54444"][/post]​

G'day Ross,
Do you have any analysis data on your tank water?

1tsp of calcium carbonate (Chalk) weighs around 1.8 grams which adds 105ppm Ca and 158ppm CO3 at a concentration of 1 gram per gallon. Calcium Carbonate also tends to RAISE the pH of the mash. Therefore, if you mashed with only 1 Gallon of water, for example, you multiply the added amounts of Ca and CO3 by 1.8 (1 tsp). 2 Gallons of mash means multiply the single teaspoon concentrations by 0.9 (2 Gals / 1.8 grams) etc, etc...How much mash water did you have?

Now, 1tsp of Calcium Sulphate (Gypsum) yields about 4 grams of Gypsum which is 61ppm Calcium and 147ppm Sulphate at 1 gram per gallon. Gypsum tends to LOWER pH. Generally, 1 to 1.5tsp in a full boil volume is fine - assuming you need Gypsum in the first place :blink:.

A half tsp of Magnesium Sulphate (Epsom Salts) yields about 2.25 grams or 26ppm Magnesium and 103ppm Sulphate at 1 gram per gallon. Magnesium Sulphate also tends to slightly LOWER the pH.

To work out the amount of Calcium, Sulphate and Magnesium in your mash and boil solutions, you need to apply the above levels and dilute based on the boil size - but note that we're adding ions and some other things occur so its not all perfectly linear like adding "3 drops of sinister sauce..."!

As I mentioned earlier, you can't really tell how effective these additions are without having an idea of you starting water profile - if you already have high sulphate levels, for example, then adding Gypsum can be quite detrimental to the final outcome.

Cheers,
TL

 

[Ross]

TL,

I have no idea what my water analysis is - but assuming its fairly soft being just rain water....

My boils are approx 37L to produce 26L into the fermenter...

Cheers...

 

[sosman]

Rolled oats are fine Ross. Just bear in mind that 500g could lead to a slightly sticky (even stuck) mash. I'd cut them in half personally. YMMV

[post="54420"][/post]​

Every last one?

 

[sosman]

I basically mash for 60 minutes. I have only ever once ran an "iodine test" and even though the test technique was not optimum (see notes on web page) things seemed to progress lots between the 30 and 40 minute mark of the mash.

http://brewiki.org/IodineTest

Also, since I am getting well over 80% efficiency with 60 min mashes, I see no reason to suggest they should be longer.