Designing Stronger Beers

[Ronin]

I was just playing around in beersmith, and was wondering about designing an imperial stout. Say my normal recipe for a stout calls for (and i've simplified the recipe to make my question easier):

4.5kg pale malt 90%
0.5kg roast malt 10%

If I was to design a imperial stout, would I simply double (again for simplicity) the recipe while keeping the ratios (90%/10%) the same, or would I keep the amount of roast malt (0.5kg) the same and increase only the base malt, bringing the roast malt closer to 5%? If you look at the style guidelines for dry/oatmeal/imperial stouts the maximum colour is the same, implying that the total amount of roast malt in the grist should be the same.

I guess what I'm asking is it the ratio of base to specialty malt that's important or is it the amount of specialty malt that's important, irrespective of the gravity of the wort? I'm leaning towards keeping the amount of specialty/roast malts the same while increasing the base malt, so changing the ratios of the grains, but i'm not 100% sure.

Have I explained what I'm asking well enough? Thoughts anyone?

James

 

[Dave86]

I haven't experimented much with this sort of thing but I'd say its somewhere in between. A kilo of roast/black malt in a 20-25L batch would be pretty ordinary to my tastes, but you would want to increase it slightly froma normal stout recipe as the extra malt may make it a bit cloying

 

[Cortez The Killer]

Here's an article on point

The IBU's were directed to it when the theme for Iron Brewer was Imperialisation

The latest BYO also has an article on point

Cheers

View attachment Thinking_Big.doc

 

[Ronin]

I haven't experimented much with this sort of thing but I'd say its somewhere in between. A kilo of roast/black malt in a 20-25L batch would be pretty ordinary to my tastes, but you would want to increase it slightly froma normal stout recipe as the extra malt may make it a bit cloying

Yeah I though the answer might be somewhere in between (like all helpful answers ). But what about extra bitterness from hops to balance the extra gravity, not from the roast malt. RIS can be up to twice as bitter (according to the BJCP, which I know are just guidelines), so as long as you keep the BU:GU around 0.8-0.9 it should counteract the extra malt in there and balance the beer?

I know there's only one way to solve this and just brew a few, which I'm sure I'll do. I'd like people's opinion first.

james

 

[Ronin]

Here's an article on point

Thanks Cortez, that looks like exactly what I'm after from a quick look. And it looks like it's the middle ground that's the way to go.

I'm not sure I understand how have the same amount of roast malt in two beers (one normal gravity and one big beer) can end up with completely different colours. Surely the colour from a roast malt is extracted from the husk regardless of the gravity?

 

[Adamt]

You have to remember there is colour from the base malt as well...

 

[newguy]

I lucked out and brewed a killer RIS about 18 months ago. It's just now coming into its own with the oxidative qualities rounding out the flavours. Anyway, my recipe is below (42l finished volume). I used a fresh wort kit available around here made by a company called Brewhouse. The kit I used was a Munich dark lager. I used the kit as part of the "water" for my all grain infusion. If you can find a similar FWK, they're a fantastic way to make up part of your gravity for heavy beers.

Grist:
9.93 kg 2 row
1.39 kg roasted barley (8% of the grist, not counting the contribution from the kit)
491 g chocolate malt (4% of the grist, not counting the contribution from the kit)
1 x Brewhouse Munich dark lager FWK (approx 17.5l of liquid - enough for 21l of ~1.050ish wort by itself)

Mashed @67C for 60 min.

Hops:
156 g Chinook pellets (12.0%) 90 min (approx 78 IBU with another ~5 IBU from the kit)

Yeast:
Wyeast 1318 London Ale III fermented @ 15.5C - 17C for 3 weeks.

OG 1.091
FG 1.026

 

[drtomc]

The chemistry of extraction is complex, and something that I'll leave to others who actually know something about it (I *failed* 2nd year physical chemistry which is why I went and studied computer science instead ), but in general the proportion of solubles that make it into the wort is less for a high gravity wort than for a low gravity wort. Also, some compounds are more soluble than others, so at a given gravity you might extract 75% of the simple sugars and 40% of the coloured compounds, at a higher gravity you might get 70% of the simple sugars but only 20% of the coloured compounds.

It's all too complex. Just brew two half batches and try different proportions. Or even better, brew four half batches...

T.

 

[Ronin]

You have to remember there is colour from the base malt as well...

Yeah but the article cortez provided seems to suggest that if you leave the amount of roast malt the same and only increase the base malt (i.e. the % or roast malt decreases), the beer will actually be lighter in colour than the lower gravity beer it's based on. That seems a little counter intuitive to me. It implies that the colour of a beers is based on the % of malts in the grist, not the total amount of specialty/roast malts in there.

 

[Ronin]

The chemistry of extraction is complex, and something that I'll leave to others who actually know something about it (I *failed* 2nd year physical chemistry which is why I went and studied computer science instead ), but in general the proportion of solubles that make it into the wort is less for a high gravity wort than for a low gravity wort. Also, some compounds are more soluble than others, so at a given gravity you might extract 75% of the simple sugars and 40% of the coloured compounds, at a higher gravity you might get 70% of the simple sugars but only 20% of the coloured compounds.

It's all too complex. Just brew two half batches and try different proportions. Or even better, brew four half batches...

T.

Yeah I was wondering if the colour compounds and the sugars are extracted at different rates. If they are then that explains the phenomenon described in the article above. I knew that you had to adjust efficiency when you're increasing the gravity of a wort to take into account the lower sugar extraction, but I didn't know that sugars and colour compounds are extracted independently at different rates.

So in that case, where do the roast flavours in a stout come from, are they linked to extraction of the colour compounds or the sugar compounds or are we adding a third variable here?

 

[drtomc]

So in that case, where do the roast flavours in a stout come from, are they linked to extraction of the colour compounds or the sugar compounds or are we adding a third variable here?

I was just using simple sugars and colour compounds as hypothetical examples. There are lots of variables - temperature, water profile, etc, etc. Someone who knows more advanced brewing chemistry can probably give you a more detailed answer (DrSmurto, perhaps?), but ultimately, there is no real substitute for experimentation. Besides, experimentation is fun.

T.

 

[Bongchitis]

....(I *failed* 2nd year physical chemistry which is why I went and studied computer science instead

Hahahaha I failed aswell, well actually a terminating pass... might as well = FAIL

... only to become a Chemical Engineer and I still hate physical chemistry. :icon_offtopic:

 

[jayse]

I think you'll find this thread helpfull, it seems doubling the roast portion is actually the way to go and amounts of brown and amber which you'd normally screw your nose up at and think is insane to be the go.
This here is from the thread.

This is probably one of the few styles I've brewed enough to have something of value to say, so here are my thoughts:

Malt:
- I am of the opinion that crystal malt (particularly) and Munich-type malts have no place in an imperial stout. With a gravity near 1.1 you're going to get plenty of malt flavour and sweetness anyway. These guys just make it even sweeter and flabbier.
- Specialty malts that give a 'drying' effect are great. Amber and brown malts particularly, at levels you would otherwise never even consider.
- Load up on roasted barley. I reckon you need a higher % of RB in an imperial than a dry stout, so that's usually >1kg in a batch. Add significantly smaller amounts of choc and/or roast malt for "malt complexity."
- Base malt isn't a huge concern, but obviously Maris Otter is very good. Mash real low because all the roasted malts/grains usually give a higher FG (they do for me, at least.) I usually aim for about 1.100 as an OG.

Hops:
- My preference is to avoid US varieties because I don't really like the pine/coffee clash of flavours, but other than that anything goes. I quite like PoR actually. I will never brew another imperial with less than 100 calculated IBUs either.
- I don't bother with hop flavour or aroma any more. I think it tends to clash with the dark malt/grain flavours, plus I like to age them for years anyway by which time most of the hop character is gone anyway.

Yeast:
- I've had good results with Wyeast 1056 and 1084, and S-04 and US-56.
- The only yeast I wouldn't recommend for this style is Wyeast 1028. It's always thrown lots of higher alcohols and weird artificial cherry esters in imperial stouts for me.

Water:
- Make sure you know what you're doing with your water. The huge amounts of roasted barley required will have quite a significant lowering effect on mash pH if you've got soft water.

Age:
- I usually give them a month in primary and three to six in secondary, then bottle with fresh yeast (just a pack of US-56 or dry champagne yeast usually.)
- These beers last for years. I always make sure to bottle in mostly small bottles and stash lots away for a few years down the track. One of the best HBs I've made was an imperial stout made with a kit, steeped grains and extra hops (as a 5L batch) - it was undrinkable for several years, but after about 4 years it was amazing. This style is absolutely the best style of beer to age. They can go for decades.

 

[Swinging Beef]

Cool article, Cortez.. where did that come from?

I really like this thread.
Im glad Im not the only one who thinks beers with less thanb 6% abv are simply yeast starters.

 

[Cortez The Killer]

The reverend doctor posted it for Iron Brewer #2

Cheers

 

[mje1980]

Yeah but the article cortez provided seems to suggest that if you leave the amount of roast malt the same and only increase the base malt (i.e. the % or roast malt decreases), the beer will actually be lighter in colour than the lower gravity beer it's based on. That seems a little counter intuitive to me. It implies that the colour of a beers is based on the % of malts in the grist, not the total amount of specialty/roast malts in there.

THat makes complete sense to me. I use percentages, not kilo's to calculate grist. ITs simple really. Base malt with .5% black is going to be much lighter than base malt with 5% black. Simple.

 

[Ronin]

THat makes complete sense to me. I use percentages, not kilo's to calculate grist. ITs simple really. Base malt with .5% black is going to be much lighter than base malt with 5% black. Simple.

I understand how the percentages work. It is simple when the amount of base malt is the same in each grist. 0.5% of 5kg is 25g roast malt and 5% of 5kg is 250g roast malt. The second one will be much darker. Obvious.

But what if the amount of total malt in the grist is increased so that the amount of specialty malt is the same. So keeping the volume the same:

Wort 1 = 5kg total malt in 20L with 0.5% roast malt = 250g roast malt = Weaker, darker beer

Wort 2 = 10kg total malt in 20L 0.25% roast malt = 250g roast malt = Stronger, lighter beer

As you can see the amount of roast malt in each grist is the same, but apparently the higher gravity wort 2 will have a lighter colour than the lower gravity wort 1. I'm not sure if this is actually the case but this is what the article supplied by cortez says will happen. I would've assumed the colours would be the same, if not wort 2 slightly darker due to the extra base malt. I'll have to experiment to find out I know, but it's pretty unusual I would've thought.

I did do one imperial stout once, and what I did notice is that you can't sparge for as long because the volume of strike water was about as much as you needed in the kettle. So a lot of colour (and I'm assuming sugars too), was left in the mash tun (which I'm assuming is where your second beer comes from). I wonder if you sparge with the normal amount of water to get all the colour compounds out of the mash of water followed by a really long boil to hit the final volume the colour would be as dark as expected.

What a shame, I'll have to brew some high gravity beers to find out :icon_cheers:

James

 

[hazard]

Wort 1 = 5kg total malt in 20L with 0.5% roast malt = 250g roast malt = Weaker, darker beer

Wort 2 = 10kg total malt in 20L 0.25% roast malt = 250g roast malt = Stronger, lighter beer

As you can see the amount of roast malt in each grist is the same, but apparently the higher gravity wort 2 will have a lighter colour than the lower gravity wort 1. I'm not sure if this is actually the case but this is what the article supplied by cortez says will happen. I would've assumed the colours would be the same, if not wort 2 slightly darker due to the extra base malt. I'll have to experiment to find out I know, but it's pretty unusual I would've thought.

Intuitively, I agree. Wort 2 should be darker. It has same colour contribution from Roast malt, and additional colour from the extra pale malt.

BUT - what if extraction for Wort 1 is (say) 75%, and extraction for wort 2 is (say) 50%? A larger brew would be expected to have lower efficiency. maybe colour contribution from roast malt is themn less?

 

[Ronin]

Intuitively, I agree. Wort 2 should be darker. It has same colour contribution from Roast malt, and additional colour from the extra pale malt.

BUT - what if extraction for Wort 1 is (say) 75%, and extraction for wort 2 is (say) 50%? A larger brew would be expected to have lower efficiency. maybe colour contribution from roast malt is themn less?

Yeah I've though about differing extraction efficiencies in higher gravity worts, thanks to drtomc, as well as sugars/colours left behind in the mash tun as I mentioned above.

I usually take the lowered efficiency into account when I design a beer (i.e. 'normal' gravity beers I set brewhouse efficiency at 75%, higher gravity beers I set it at 65%). It's pretty well known that extraction efficiency of sugars does differ with increasing gravity. I haven't read much anywhere about different extraction of colour compounds at different gravities. As drtomc said, it probably depends on a lot of things.

One thing I know is that the beersmith definately doesn't change the EBC of a given recipe asthe gravity increases. Maybe too complex a situation to include.

 

[Jesse]

I am thinking about making a RIS atm.

What is the go with the BU:GU ratio? is there a topic where this is explained

I was going to do
85.1% base malt
8.1% roast barley (the dehusked stuff from WM to reduce the astringency)
3.2% Choc
3.6% Special B

to around OG 1109 and IBU = 70-80

will this be balanced with age accoding to that funny BU:GU ratio?