Two mashes or reiterated mash?

[Brewshna]

Would you share your base recipe?

 

[jerrylotto]

Would you share your base recipe?

18# 2-row pale
3# Munich
1# 60L Crystal
1# Chocolate
8 oz Roasted Barley
4 oz Black Patent

1st mash is 12# 2-row, all of the adjunct grains go into the second (iterative) mash.

Dissolve 2# light DME in the collected runnings and start a 120 min boil.

90 min 1.5 oz Nugget
30 min 1.0 oz Williamette
15 min 1.0 oz Williamette

Cool and oxygenate.

Soak 8 oz toasted oak cubes in 16 oz bourbon during the first 18 days while you ferment out on 3 packs Safale S05. Add the bourbon-soaked oak cubes and wait another 10 days before kegging.

 

[Brewshna]

Cool thanks, my newest recipe in planning isn't that far off yours

 

[Brewshna]

By the way, what could cause my beer to turn out with an FG of 9 instead of 8? I know a few reasons and would like to know what you guys think. I calculated FG using @VikeMan excel sheet calculator, thanks again for that.

 

[jerrylotto]

By the way, what could cause my beer to turn out with an FG of 9 instead of 8? I know a few reasons and would like to know what you guys think. I calculated FG using @VikeMan excel sheet calculator, thanks again for that.

Brewers yeast can metabolize sugars made up of one ( glucose, fructose, galactose ), two ( primarily maltose, lactose and sucrose ) and three ( primarily maltotriose and raffinose ) monosaccharide units. Anything larger than that and they can not metabolize them. Thus, carbohydrate units of of 4, 5 ,6 etc monosaccharide units remain in the beer as unfermentables to provide a sweetness, viscosity and elevated final gravity. Mashing at higher temperatures produces more of these larger carbohydrates due to the high temperature activity of alpha amylase. Beta amylase cleaves disaccharides (maltose) off of the end of a starch chain but is active above 140F and denatures rapidly above 160F whereas alpha amylase breaks starches less discriminately leading to higher order saccharides, is most active above 150F does not denature rapidly until you hit 170F.

 

[Brewshna]

Did mash rather high, first at 66C second at 68C. But did take that into account. Dark malts have lots of unfermentable sugars, which I also took into account. 8P should have been realistic. Maybe too little yeast? 3 packs of dry yeast should have been enough though.

 

[jerrylotto]

Did mash rather high, first at 66C second at 68C. But did take that into account. Dark malts have lots of unfermentable sugars, which I also took into account. 8P should have been realistic. Maybe too little yeast? 3 packs of dry yeast should have been enough though.

Every mash I do is a step mash, iterative or not. Starting around 100F (38C) for an acid rest, I raise the temp slowly pausing for a protein rest at 120F (49C) until I get to 142F (61C) where I stay for at least 30 min (optimum beta-amylase activity) before hitting the sweet spot around 153F (67C) where alpha and beta both thrive. After at least another 30 min, I mash out at 158F (70C) which is optimal alpha-amylase activity temperature, then sparge with 170F (77C) water.

 

[Brewshna]

How do you brew big body beers then? This way your using all the available sugar and making the max amount fermentable. Sounds great for lagers, pils etc but on some ipas you want body, especially bigger beers that need some residual sweetness.

II haven't quite understood what the acid rest is for.

 

[Brewshna]

And thanks for adding the Celsius temps

 

[jerrylotto]

Acid rest is primarily to hydrate the grain kernels and allow the mash pH to stabilize. Not of much use with kilned grains because the kilning process breaks down the enzyme phytase which is key to this step. Pretty much gone above 131F (55C). The mash pH is lowered though the production of inositol hexaphosphate aka phytic acid by breaking down beta-glucans and it is a time consuming step (up to an hour for full effect) but it also makes the starches in the kernel more accessible.

 

[Brewshna]

To reawaken my own thread as i'm planning another reiterated mash, aim is a 12%ABV beer this time. Another question I've come up with, should I mash most dark grains in the first load to stabile the pH level and this at 68C. Then mash lots of base malt with oats and a little dark grain at 66C for the second round? Looking at pH levels mainly. Can't wait to brew this 14kg malt monster. The last beer turned out lovley, just wasn't carbonated 2 weeks ago (6 weeks in the bottle) seems to need some more time.

 

[McMullan]

Do you mean double mash? If so, and assuming you treat your mash liquor, I recommend you half your grain bill and prep twice. Water treatment consideration means you want to mash two comparable grists.

 

[Brewshna]

Two following mashes using the same Wort. Halfing means adding acid. I'm sparging the first mash heavily, so I can collect enough to use that liquid to sparge the second batch. So water treatment is going to be interesting.

 

[McMullan]

I'm not sure if sparging a lot here is compatible with the aim, unless you're planning a very long boil. What you're proposing - mashing dark grains in mash 1… then base malt in mash 2 - is a clumsy strategy for a double mash, imo. I'd prep 2 identical grain bills (each containing half your recipe) and treat total water once. It works for me. Milling it all together then dividing it in two isn't advisable. Some sparging might be advisable, but, you could get a session beer out of the fermentables remaining in the grain?

 

[Brewshna]

I was going to sparge the first mash more, so I can sparge the second with Wort until I get my pre boil volume, apr 24l. I have a 30l system. I'm completely undecided on the two grain bills. Went 50/50 last time

 

[bwible]

Depending on the goal there are articles and such out there that suggest adding dark grains late. Gordon Strong talks about this in his book. Some recipes (regular single mash) he says to hold all the dark grains back and don’t put them in the mash until the end of the mash when you start to do vorlauf. I guess this is applying to the old 3 tier systems. I think the reason they talk about doing that is it lends a smoother dark malt character.

If I was to apply this to a double mash, I would put all the dark malts in the second mash with a higher percentage of base malts in the first mash. A percentage of 6 row might even be a good idea since there’s so much grain and you’re going for maximum extraction.

I only tried a double mash one time, after I read about it in Randy Mosher’s book, “Extreme Brewing” years ago and I’m just going to say I never felt the desire to do it again after that. The resulting beer actually wasn’t even that good. YMMV.

 

[Brewshna]

I've done it twice and both beers are really good. The late dark grain is meant for very dark stuff and is supposed to reduce astringency. I'm using 3.4% dark chocolate as darkest grain, rest is special B, caramel 60 and lots of light chocolate. Want a very smooth and chocolaty beer. I really love very big stouts and want to brew them to my liking.

 

[bwible]

We’re all limited by the size of our mash tuns. When I want to big beers such as barleywines or RIS I just use whatever grain fits in my mash tun then supplement that main mash with however much DME it takes to get up to the target gravity. Yes extract costs more but it all evens out in the end when you consider 2 batches of grain and all your extra time and energy to do a double mash.

 

[Brewshna]

That's true, I just really don't want to use DME. It's very expensive in Germany on top. It's just something I've got a bit obsessed with, brewing a 12% beer with no DME etc. Been thinking a lot so I wanted to throw my ideas down out there

 

[McMullan]

I use a braumeister, so quite limited by grain capacity. I double mash about twice a year and have no problems doing it the way I’ve described. If target OG is missed I add brewing sugar.

 

[jerrylotto]

I usually do the first mash with all base malt and save the specialty grains for the second iteration. Also, I use clear water to sparge both times - I use the wort from the first batch as strike for the second. It has always worked well for me and you want a larger volume for a 120 min boil anyway (which is what I typically use for the my high sugar worts).

 

[bwible]

I use a braumeister, so quite limited by grain capacity. I double mash about twice a year and have no problems doing it the way I’ve described. If target OG is missed I add brewing sugar.

I have an Anvil Foundry 6.5. It holds 8 lbs of grain. I use it for 3 gallon batches. Only so much you can do with 8 lbs of grain. Less than 4 kilos for you guys? Works well for average strength stuff.

 

[Mac's Brew]

When I brew big beers (barleywine and Imperial stout) I divide evenly to have approximately 50% of each grain in both of the two step mashes (140° F/158° F). I sparge both, collecting 50% of my wort from the first. I use extra hot liquor (at 158°) when sparging the first batch and collect the extra wort to use with the strike water in the second mash. At the end I raise the second mash to 170° and sparge with 170° clear water. To make it easy, I use 5.2 pH stabilizer in both mashes.

I usually add some DME and some dextrose to the kettle to boost the gravity. My last one (October 2021) was an English style Imperial Oatmeal Stout. 140 lbs of grain (1bbl batch, 90 minute boil), OG 1.108 FG 1.036. The first runnings of the second mash were 10 points higher than the first mash.

Since high efficiency is hard to attain with these big beers, I think a reiterated mash is a good way to increase efficiency, and I always split/mill each grain 50/50. Even so, I still have to add some DME (yes it's expensive) and limited amounts of dextrose (pretty cheap) to get close to my targets.

 

[doug293cz]

When I brew big beers (barleywine and Imperial stout) I divide evenly to have approximately 50% of each grain in both of the two step mashes (140° F/158° F). I sparge both, collecting 50% of my wort from the first. I use extra hot liquor (at 158°) when sparging the first batch and collect the extra wort to use with the strike water in the second mash. At the end I raise the second mash to 170° and sparge with 170° clear water. To make it easy, I use 5.2 pH stabilizer in both mashes.

I usually add some DME and some dextrose to the kettle to boost the gravity. My last one (October 2021) was an English style Imperial Oatmeal Stout. 140 lbs of grain (1bbl batch, 90 minute boil), OG 1.108 FG 1.036. The first runnings of the second mash were 10 points higher than the first mash.

Since high efficiency is hard to attain with these big beers, I think a reiterated mash is a good way to increase efficiency, and I always split/mill each grain 50/50. Even so, I still have to add some DME (yes it's expensive) and limited amounts of dextrose (pretty cheap) to get close to my targets.

The simulations I did for batch sparging showed that a single large mash had a slightly better lauter efficiency than an iterated mash. If you have the mash volume, go single step. If you can't get all the grain into your mash vessel at once, than go ahead and iterate - the efficiency penalty is small.

Brew on