January 8, 2016 by fhsteinbart
Most breweries around the world practice high gravity brewing on an ongoing basis. Even AB brews their famous Lagers to a higher than normal OG (~1.060), with a matching bitterness (usually and customarily around 30 IBU’s). What they then do later in the blending tanks is add St. Louis Liquor (water that has been reverse osmosis treated, then mineralized to reflect the municipal water supply of St. Louis) to get to the desired ABV and IBU before packaging. This is done to save money on tankage, but you have to be careful when making light delicate beers like this to prevent the higher gravity worts from unbalancing the flavor profile.
- High gravity beers usually result in more yeast character than what is found in more normal gravity worts. This is why most of the above mentioned breweries don’t push the envelope to far in making their beers. To avoid producing some unwanted yeast characters like fusel’s, simply ferment cooler than what you would do with a standard gravity beer. I recommend something in the low to mid 60’s for Ales, and low to mid 50’s for lagers, with a diacetyl rest after fermentation is over.
- Mash thickness should be increased to preserve the saccharification enzymes, and keep the mash temperatures in the mid to high 140’s for upwards of 90 to 120 minutes to ensure conversion. Also, a slower than usual lauter helps with extracting all those hard earned sugars made during the mash.
- Speaking of longer than standard lauters, I usually recommend 60 to 90 minutes MINIMUM to ensure that you got all those sugars from the mash tun into your kettle where they belong! You can go longer, just remember that you are diluting the mash moment by moment as you sparge, so make sure to treat your sparge water to some acid like Lactic acid, or Phosphoric acid, to maintain a pH below 6.0.
- Speaking of pH, the mash pH in a high gravity brew is the same as any other brew of regular strength, so just make sure that you are in the range of 5.2 ~ 5.4 pH, and you should be fine. By treating your sparge water with acid to bring down the pH to 6.0 or less (but don’t go any lower than 5.2!) you’ll prevent tannins and silicates from solubilizing in your wort and affecting the flavor of your finished beer. This also applies to your regular strength beers as well.
- When I mention mash thickness, I mean REALLY thick, like 1:1 w/w of your grist and hot liquor. I generally use 1 lb. grain per 1 qt. hot liquor (1Kg/2l for you metric folks) which makes for difficult mixing, but I use and highly recommend a mash mixer like the Mix-Stir.
- When the boil commences, I recommend boiling just as soon as the wort covers the bottom of you kettle so that you boil throughout the wort collection. This saves time, and will produce more melanoidins, which when left in an unoxidized state will aid in aging bigger beers.
- Hops, you need a massive amount of hops to balance the higher osmotic pressure placed on the hops. Your kettle utilization rate will drop precipitously to sometimes half of what you’d usually get with a more normal gravity wort. This doesn’t mean that you just double up on the hops and you’re good to go. Rather you should consider adding 3 or 4 times the amount of hops for a standard strength beer, otherwise it will taste too cloyingly sweet, unless of course, it’s bone dry. Drier beers are easier to drink, so you may wish to consider adding some simple sugars like corn sugar to make the wort even more fermentable.
- Yeast, lots and lots of yeast. While I’ve always been an advocate of pitching large quantities of healthy active yeast to even standard strength beers, you need to add even more yeast than that for a bigger beer. How much you ask? Well, a gallon of slurry per 5 gallons is about right. I typically reuse my yeast in serial brewing of stronger beers based on style similarities. For example, I’ll make a Pale Ale, then I’ll pitch an IPA on top of the Pale Ale yeast cake, then I’ll pitch my big beer on top of that yeast cake, which makes for a good healthy fermentation, even at cooler than normal temperatures.
- Time, yes time, that one thing we can’t do much about except to manage it better. Aging of big beers is a no brainer, you simply leave it in a place with a constant cellar temperature or cooler (I prefer 35° F, or 1.67°C) to gracefully age over the ensuing years. Most big beers take at least six months before they are enjoyable, and a year is better still. As for packaging, I prefer kegging for its consistency. You can also bottle, but be sure to use fresh healthy yeast at bottling time, as the yeast used in fermentation will be more than likely too worn out to referment properly. You may also elect to add some Brettanomyces Bruxellensis to your beer to give it a drier, more earthy Farmhouse flavor and aroma like some Belgian brewers do. All in all, the making of big beers is not that difficult a challenge, provided that you use sound brewing practices like I outlined above, and try to think of bigger beers in a different way than you have before. Good luck, hoppy brewing, and enjoy your brews!