As my poll stands now, a high gravity beer is in the future. What constitutes high gravity? This differs from person-to-person, but I like to think anything with a starting gravity of 1.060 as high gravity. There are many challenges when brewing a high gravity beer. I hope to discuss the potential areas to-watch out for, as a written post to my readers, but also as checklist to myself to produce a quality beer.
Extract Efficiency - Generally in a high gravity beer there will be less, if any, water used for sparging. This is due to the increased grain bill and volume of liquid needed to be collected for the boil. This means that the chances for extracting all the sugars (through sparging) like one normal does is not possible. In general homebrewers tend to agree that your efficiency will suffer 10%-15% from your normal. Trial and error is key for this, but as a first time All Grain high gravity brew, I will have to guestimate.
Longer Boil - A lot of times to increase the amount of sugar in the wort, a brewer will employ the use of a longer boil. This increased boil time will evaporate more water and result in a more concentrated sugar content in the wort. This technique is used on a lot of bigger beers
Simple Sugar - Often a frowned upon ingredient in homebrewing circles, a simple sugar can be a critical component of a high gravity beer. Up to a certain level the use of all grains can produce to many unfermentable sugars and create a beer that is too thick and full bodied. Although tasty, it would be hard to consume more than 4 oz of such a beer. Simple sugars are used in a lot of high gravity beers like belgian triples and imperial IPAs. 10%+ simple sugar or so, depending on recipe, can greatly increase the drinkability of a beer and not impart any thin or cidery flavor impact.
Hops - There is a lot of science behind this, but with higher gravity wort your hop utilization rate drops significantly. This will require more hops then one would expect. I highly recommend brewing software to help formulate an IBU estimate. Additionally, a lot of high gravity beers will be aged for months to years. The bitterness will fade over time. You also need to balance out the higher expected final gravity (residual sweetness) associated with a big beer through a higher IBU level.
Yeast - Lets face it, yeast health and happiness is always important to producing great beer, but brewing a high gravity beer it is imperative. High gravity beers produce a very stressful environment for the yeast. If you can't get the correct amount of healthy yeast, I recommend not brewing this style. I plan on using a rinsed yeast cake from my pale ale (which I really need to keg, but guess that will happen next week). If you don't have access to a large yeast cake then you should use multiple packs of rehydrated dry yeast. Properly control the temperature of fermentation, and make sure to aerate the wort prior to pitching.
Recipe - Balancing a high gravity beer is a tricky procedure. I highly recommend working with a known recipe for a first attempt. You want to focus on factors to produce a beer that your palate will enjoy. The yeast I am using is WLP002 which is a low attenuating english yeast. I plan on mashing really low for longer than usual and potential using some table sugar to dry things out. As always, keep detailed notes so changes can be made to future brews.
High Gravity Brews require more prep time, more brewday time, and more waiting time until you can consume. Given the time associated with a high gravity beer I want to do all that I can to make it successful. Hopefully my first experience will be positive. Unfortunately we will have to wait a half a year or so to find out!
