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> Big Beer How To FAQ, contributed by bonjour
cj in j
post Nov 25 2005, 10:06 PM
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How to Brew a Really BIG Beer FAQ
contributed by bonjour

1.050, 1.060, 1.070, 1.080? You have to be kidding! I mean really big beers. These starts at 1.100 and go up from there. I can buy a lot of beers, but very few of them are truly big. Life begins at 100, 1.100 that is. Let’s hear it for “century” beers!

I brew mostly all-grain beer so this FAQ is aimed toward all-grain brewing, but all things (except for the mash schedule) that we need to consider are important for both all-grain and extract brewing.

The Numbers
What happens when you brew an all-grain BIG beer? Obviously the yeast ferments a portion of the sugars available giving you beer. Life is simple and beautiful, but the yeast has been having a tough time.

The first step is to decide what we would like our OG to be. No magic here -- formulate your grain bill in your normal manner. We will discuss modifications and the reason for them later.

Next, choose a target FG. Yes I said Final Gravity. Part of the art of brewing a truly big beer is to hit your FG. Let’s talk about that now. The achieved FG departs a lot of character to your beer, mostly in mouthfeel and residual sweetness. How dry or sweet do you want your beer? The residual sweetness left behind determines a lot of the character in the beer. The FG is very difficult to predict -- none of the brewing software packages can truly predict FG (they assume an average attenuation for the yeast used), and none of the current literature addresses this. So we each have to deal with this based on our experience and the principles of what we can do to impact FG.

For a style I’m going to choose one of my favorites, an English Barleywine. The style guidelines (BJCP Style guideline at BJCP.org) say:

-- OG = 1.080 - 1.120+
-- FG = 1.018 - 1.030+
-- IBUs = 35 - 70
-- SRM = 8 - 22
-- ABV = 8 - 12+%

Let’s look at a 1.080 Barleywine that finishes at 1.020. This is an attenuation of 75%, easily attainable with most grain bills and most yeast. Let’s look at the upper end of the spectrum, a 1.120 Barleywine that finishes at 1.030. This again is an attenuation of 75%, though a harder-to-achieve 75%. By the numbers, these two Barleywines are similar; however, they will have very different characters because of the different FGs. Let’s look at one more, a true monster, a 1.150 Barleywine with that same 75% (now very difficult to achieve) attenuation, an FG of 1.038. Just looking at the numbers, it seems reasonable.

However, brewed using the same techniques, I would expect the FG to be a bit higher, say 1.045-1.050, which IMHO is a bit too high and into the “cloyingly sweet” category. The 1.120 Barleywine I would expect to finish with a FG of 1.035-1.040. In other words I expect the Big Barleywine to drop approx 5% attenuation because of the difficulty the yeast will have in a high-alcohol environment. The bottomline, when brewing BIG beers we need to get our attenuation up to achieve an FG lower than we would normally achieve.

These attenuation issues can be addressed with several variables including paying careful attention to your yeast, yeast selection, grain bill, and mash schedule.

Starter
A “pitchable” tube or an Activator Pack is NOT enough yeast -- a starter is definitely needed. A starter – no, make that a large starter, a cup of thick slurry (or yeast sediment) from a pervious batch, or even pitching on top of a yeast cake is needed for BIG beers. With BIG beers you really can’t have too much yeast.

Wort Aeration
Your wort needs to be well oxygenated or aerated to provide a good environment for your growing yeast. Vigorous agitation, which is what I do, is sufficient, although direct oxygenation with an O2 gas injection system would be better. Once the wort is safely cooled below 85F, I rapidly move my immersion wort chiller up and down through the wort effectively completing the chilling of my wort and aerating it at the same time.

Rousing
As the yeast is completing its task, it is flocculating or falling out of solution. It does not matter is the yeast flocculates at a high or a low rate, with a big beer it will flocculate out before fermentation is finished. To compensate we must rouse the yeast at frequent intervals to keep the yeast in suspension and give it a chance to ferment the remaining fermentable sugars. The minimum would be to rouse the yeast 2-3 times per day (before you go to work, when you get home, and just before you go to bed.) Ideally rouse the yeast on a continuous basis. This does not need to start until fermentation is slowing down.

Yeast Selection
Since we are dealing with attenuation, the obvious answer is to select, if possible, a more attenuative yeast. In some styles all you are looking for is a neutral yeast; in others you need the character of the yeast to come through. For those times when you want some yeast character, you may consider a yeast blend, a neutral high-attenuative yeast and your character yeast. My last Barleywine used a 1007 German Ale yeast cake and a 1318 London Ale starter for a bit of English character.

Grain Bill
The problem we are fighting here is a high FG -- we want to squeak as much attenuation as we can out of our brew. First let’s limit our use of malts which yield higher FGs, the crystals and carapils type malts. Additionally we can add some sugar, up to 10%, (remember this is not some BMC light beer we are trying to brew) -- there is more than enough malt backbone here to carry the sugar. Almost any kind of sugar will do, but I like to add a “character” sugar. Some you might want to try are maple sugar/syrup, molasses, brown (light or dark) sugar, honey, candi sugar, as well as plain old ordinary white cane sugar. All of these sugars are more fermentable than wort and will effectively lower your FG given the same OG because they are all nearly completely fermentable.

If you are using extracts, do not use the lower fermentable extracts (such as Laaglanders, which is great in a Scottish 80/-). You will have plenty of non-fermentables from the size of your grain bill.

Mash Schedule
Here is some general information on mash temperatures. Attenuation is highly influenced by mash temperatures, and for different mash temperatures you can expect a different attenuation range. This chart is an interpretation of attenuation in an infusion mash from Noonan’s book. With a single infusion mash at 149F, Noonan says in New Brewing Lager Beer, an attenuation of 75-80% usually results. This chart highlights the fact that to maximize attenuation we want to mash at the low end of this curve.
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For a big Belgian, which by style has a dry finish, you will also need to mash for high fermentability. The BJCP style guide for 18E, Belgian Dark Strong Ale says:

-- OG = 1.075 - 1.110+
-- FG = 1.010 - 1.024
-- IBUs = 15 - 25+
-- SRM = 15 - 20
-- ABV = 8 - 12+%

This indicates an 80-87% attenuation of the wort. For Belgian Golden Strong Ale, BJCP style 18D, the target attenuation is 83-86%. If you are brewing a big thick beer such as a Thomas Hardy clone or a Wee Heavy, you want a higher than normal FG. For a normal strength beer, up to about 1.080, you would perform a single step infusion mash of around 155-158F to achieve this. If you were to attempt this with a 1.120+ beer, though, you could probably sell the result as molasses (just kidding a little bit). What is needed is a counter-intuitive highly fermentable mash schedule. I would suggest a step mash first resting at 146-149F for about 40-45 minutes followed by a rest at 154-156F for around an hour. Do not be afraid to extend your mash times. While conversion occurs quickly (10-15 minutes), Noonan say, “A 120-minute mash is going to eke out every bit of diastatic power that the malt has to offer.”

Also we want to go with a thin mash, greater than or equal to 2 qts/lb of malt, to promote greater fermentability. We want to give lots of time to breakdown the complex sugars (not the starches) into simple, more fermentable sugars. For those of us who use coolers for a mash tun, there may not be enough room for an infusion big enough to effect the temperature change, especially with a really big beer. In that case, use a decoction. A decoction is a time-proven method of stepping up mash temps. While today’s malt doesn’t require a decoction for conversion, it is very effective for achieving target temperatures in step mashes. Brewing is an art -- we may choose to use or not use any or all of these tools, but these are what we have to manage the mash.

Other than FG, what other problems can we run into in a BIG brew?
Additional obvious problems that we may run into are high fruitiness and ester production and high fusel alcohol production. These are best managed by yeast selection and fermentation temperature control. Because of the large amount of fermentables you are using in a big beer, it stands to reason that all the yeasts byproducts are concentrated in your beer more than with a standard strength beer. Fermenting cooler than normal, as with any ale, will trend towards lager characteristics which include reduced ester and fusel production. Again, the volume of the grain bill with the higher level of fermentables will tend to keep these key ale characteristics near normal ale levels.

Yeast Selection (again)
To reduce the esters retained in your beer, you may want to choose a different yeast. Choose a yeast that is more restrained in ester production than you would have otherwise chosen. However, the more important factor, IMHO, is fermentation temperature.

Fermentation Temperature
Fermentation temperature, I believe, is the largest single success factor in brewing a BIG beer. High ester and fusel alcohol production is a function of yeasts working at higher temps. Ideal fermentation would be at 55F (yes, this is for an ale) with Wyeast 1007 German Ale or 1728 Scottish Ale. I would also consider Wyeast 2112 California Lager. For those in the ice belt, your basement during December/January should be fine.

As primary fermentation is slowing down and is mostly complete, raise the temp to the high end of “normal”, 66F for Wyeast 1007 and 70F for Wyeast 1728. At this stage the character of the beer is already determined. The goal is to make the yeast “warm and cozy” and keep the yeast “awake” by rousing them and get a few extra points out of them.

Bottling Considerations
As the alcohol levels go up, the yeast are getting weaker and weaker. They have reached a point where they will have difficulty consuming the “bottling sugars” you have added to carbonate the beer. In addition, frequently the “bottling sugars” are unevenly mixed resulting in inconsistently carbonated beer. If possible, you should consider Counter-Pressure filling your bottles especially when your OG is over 1.130.

Many people are scared of brewing BIG beers or have given up brewing them after an initial “less-than-perfect” attempt. But, there’s no reason to be afraid. Just be careful about the factors discussed above and you’ll be on your way.
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