Brewing Big

January 1, 2014 By K. Florian Klemp

It is always assumed that subtle, low-gravity beers are the greatest challenge in homebrewing. But high-gravity, boldly flavored beers also present some difficult hurdles. Nearly every aspect of their construction, from recipe formulation to proper maturation, entails some prudent, crucial considerations that more modest brews do not.

I consider anything above OG 1080 to be high-gravity. Definitive styles within this framework are some Belgians (tripel, strong golden, strong dark, quadrupel), barley wine/old ale, wee heavy, imperial stout, double IPA, doppelbock and imperial/Baltic porter. Beyond those, any well-planned “imperialized” or personalized brew can be crafted with canny high-gravity methods. Following these few guidelines will create excellent heavyweight beers that will burst with character or age gracefully in your cellar.

Creating a Monster

Great beers evolve from intelligently designed recipes. As with any other brew, the choice of hops and hop schedule, base malts or extract, specialty grains, yeast and mash temperature will determine the attenuation, balance, mouthfeel and especially flavor, all of which are greatly exaggerated in big brews. With these, though, it is also about hitting the target gravity to pull everything together.

Savvy extract brewers may have an advantage for brewing big beers, as mashing and extraction efficiency is immaterial. Reaching that target gravity is largely a function of using enough extract. Liquid malt extract contributes about 1036 gravity points per pound per gallon, and DME, 1045. Each pound of steeped specialty malt will contribute another 1025 points. As a simple reference point, 5 gallons of fermentable wort, OG 1080, will require 11 pounds LME or 9 pounds DME. Each pound of properly steeped grain will add 1005 points.

Boil as much wort as possible for full and proper hop utilization and proper hot break, with a full wort boil of 6 to 6.5 gallons optimal. Three gallons of concentrated wort, to be diluted later, would be enormously dense and difficult to work with. Hot/cold break and hop litter alone would take up a gallon of the kettle after chilling.
One easy, and delicious, way to increase wort gravity is by the addition of some sort of sugar. Some styles essentially require it, but many others can be enhanced greatly by it. The many varieties of sugar, including honey, offer an excellent chance to tweak and experiment. It contributes roughly the same gravity as extract, liquid or dried, depending on the sugar.

All-grain brewers have an entirely separate set of puzzles to solve with big brews. The first consideration is the size of the mash tun and its capacity. The batch can be scaled down from the normal wort yield to maximize the utility of the tun. I have a 60-quart cooler mash tun that can easily handle 35 pounds of grain, or enough for 8 to 10 gallons of strong wort (1.080-1.100). Extending the boil to 2 hours or longer while running off slowly can maximize the mash even more. If the kettle gravity is below the target, augment the wort with some malt extract.

Invariably, the runoff will be stopped sooner, leaving a lot of fermentable wort in the mash tun. Consider collecting and freezing some of this for yeast starters or investigate parti-gyle brewing.

Partial-mashers get the best of both worlds, great control over the recipe and no issues with adding extract or sugar to hit gravity.

Hopping Big Brews

Brewing strong beer will really test your hop utilization and scheduling skills. At the minimum, they require enough hops to offset the huge malty flavors in fuller, sweetish brews, but need to shine through in hop-accented brews. Utilization may be reduced to 15 percent or less in the kettle. All brewers should pick one of the several utilization equations and stick to it. It will simplify monitoring hop rates and profile characteristics from batch to batch.

Familiarize yourself with the crucial concept of the bittering unit to gravity unit ratio (BU:GU). This is critical to getting proper hop profiles. Eighty IBUs may seem high, but in the presence of 1090 wort is not that impressive, and may even be low for a particular type of beer. BU:GU eliminates any problems associated with wort gravity and desired balance.

A hoppy brew may require up to a pound of hops for a 10-gallon batch, so ensure that your kettle can handle this amount without sacrificing excessive wort. Pellets may be the answer in this case. Aromatic additions need to also be increased appropriately since the wort density will lessen the dissolution of the aromatic compounds. It will also help cut through the intense malty aromas. Bear in mind that hop bitterness, flavor and aroma diminish over time, so figure that into the equation if prolonged cellaring is part of the plan.

Arousing the Beast

Fermentation requires some serious attention. Stuck fermentation will ruin a beer, leaving it cloyingly sweet, rife with off-flavors and impossible to properly condition and carbonate. To start on the right foot, vigorous aeration is imperative, as is ample exuberant, healthy pitching yeast. Spend extra time aerating the wort and an extra day or two building up a liquid yeast culture. Always check the alcohol tolerance of the yeast you choose, so it doesn’t peter out when you need it most. If dried yeast is used, hydrate an extra pouch to pitch. With lower fermentation/pitching temperatures and longer lag time, high-gravity bottom-fermenters especially require attention to aeration and yeast vigor.

Ferment in the mid to lower range of the recommended strain temperature, as the exothermic effect of vigorous fermentation will raise the wort temperature by several degrees. Pitch a few degrees below the upper end of the suggested temperature range because once it blasts off, that rascal will laugh at your attempts to control it. Leave plenty of head space, especially for yeast that is notoriously eruptive and rocky. Geysers from clogged blowoff tubes or airlocks will make your plan to brew big seem pretty dumb.

Expect primary fermentation to take a little longer than normal. After you think it has finished, leave it for another few days. If you are doing temperature-controlled fermentation, raise the temperature a couple of degrees to check for an increase in activity. If using glass, shine a flashlight through the wort to check for clarity. Three to five weeks is not abnormal for big wort, even longer for bottom fermentation.

Even if secondary fermentation isn’t part of your regular schedule, it may be a good idea to use it. Racking will get your precious nectar off the autolyzed yeast and proteinaceous trub and also arouse the live yeast. While racking, take a taste; the flavor and mouthfeel may offer the most important clues regarding the progress of fermentation. Top up your secondary fermenter to within a couple of inches of the airlock if necessary, allowing a little room for a potential reawakening of fermentation. Secondary fermentation and conditioning can last for one to several months. For strong lagers, the secondary can serve as the lagering vessel, also, provided that primary fermentation was complete and there was little carryover of trub during the rack. Patience is always virtuous.

Bottling and Aging 

When fermentation has finished, it is time to package. Kegging needs no special attention. Bottling, on the other hand, can be tricky. Even if it seems that fermentation has run its course, there may still be a bit of fermentable sugar lurking about. Prime with no more than ¾ cup corn sugar per 5 gallons of wort. This will provide suitable carbonation, but consider using 2/3 cup of priming sugar to be safe. A dose of fresh yeast during bottling is always a good idea, since any left in the secondary is likely to be tuckered out. Treat it like pitching yeast to ensure vigor during maturation. Either the original or similar strain will do.

Waiting for beer to properly mature, condition and carbonate is always painstaking, but these will require at minimum a couple of months. Some may not reach their peak until after a year or much longer. The one exception would be hop-forward beer like double IPA or American barley wine, since those intoxicating aromatics would wither within a shorter period of time. If made well, all of these brews should stand the test of time.

American Barley Wine

All-Grain Recipe, 5 gallons, OG 1.100, 80 IBU

Mash 2# 20°L crystal malt,
3# Munich malt and 15# American 2-row malt for one hour at 152° F

First Wort Hops: 2 oz cascade

Bittering Hops, 1-hour boil: 30 AAU Chinook
Flavoring Hops,
30-minute boil: 12 AAU Centennial

Aroma Hops, 5-minute boil: 2 oz Cascade

Flame Out Hops: 2 oz Cascade

Ferment with Wyeast 1056 or 1084 or
White Labs WLP001 or WLP004

Note: Fill kettle to 7 gallons and increase boil time to 90 minutes

Imperial Stout

(Extract/Steeping Grain, 5 gallons, OG 1.090, 70 IBU)

Steeping Grain: 1.5# roasted barley,
0.5# chocolate malt, 1# 80°L crystal malt

Extract: 3# Munich malt extract,
7.5# light LME or 6# light DME

Bittering Hops, 1-hour boil:
25 AAU Northern Brewer

Flavoring Hops, 30-minute boil: 10 AAU Fuggles

Aroma Hops, 5-minute boil:
1.5 oz East Kent Goldings

Ferment with Wyeast 1028 or 1084,
White Labs WLP013 or WLP004

Note: To get proper hop profile,
fill kettle to at least 6.5 gallons