Going Big!

Going Big!
There comes a time for all home brewers that the decision to tackle a bigger beer
than any they have brewed before is made. Big beers like Imperial IPAs, Dopple
bocks, and Baltic Porters require special handling to ferment to completion.

You were asked to pick which experiment I should tackle and the majority voted for
Eisbock. An Eisbock is a dopple bock that is freeze concentrated. I typically don’t
brew big beer styles like the dopple bock so it took a little work that I thought I
should share. There are 5 essential topics to cover when talking about big beers.
The first topic is what exactly is a “Big Beer”? Many publications will say a big beer
is anything over an original gravity of 1.070, or maybe anything over an ABV of 8%. I
say a big beer is anything that requires more grain or extract than you normally use.
If you often brew a 7% AVB beer then an 8% beer won’t be that much bigger. But if
you normally brew beers in the 5 to 6% range then that 8% beer will require some
extra work.

Second topic is all about volume. Whether you brew extract or all grain, you need to
realize just how much it takes to go big. The Eisbock I brewed used 23 lbs. of grain
for a 5 gallon batch. My mash tun didn’t have enough space to hold all the grain and
strike water, let along the sparge water. Previously I’ve brewed a barley wine that
had 20 lbs. of grain and that was pushing the limits. Knowing this, I was able to
borrow a larger mash tun from my friend. Estimating the amount of grain and water
you can safely mash, or the amount of LME you can add and still have room to boil
can be difficult. I used the slowly go bigger method. If you normally brew with 14
lbs. of grain try going up to 20lbs. If you use 8 lbs. LME try going up to 14 lbs.
Third on the list is for all grain brewers. Mash low! Low mash temperatures will
increase the fermentablity of the wort. Aim for 149 degrees Fahrenheit over a 90-
minute period. This lower temp will create shorter chain sugars, which are more
fermentable by the yeast. If you mash too high the yeast will slow down and stop
before getting anywhere near done. Even with the extra fermentable wort you’ll still
end up with a full-bodied beer. Extract brewers will have trouble getting big beers
to ferment enough to not be sweet. Even the best, freshest extract has a predetirmed
fermentablility. If you go big with extract pay extra attention to the next two topics.
Forth is oxygen. Yeast need oxygen, especially when you’ve brewed a big beer. Yeast
use the oxygen to build up their cell walls, to multiple themselves, and generally to
be healthy enough for a strong fermentation. If you use the rock and splash method,
you’ll need to splash for about 3 times longer than normal. If you use an air pump or
oxygen tank, double the amount of time you normally use.

Lastly on this list is yeast. Yeast eat the sugar and convert is into alcohol and carbon
dioxide, in essence they make beer. We home brewers can’t truly control the yeast;
we just try to create the most optimal environment we can for them and hope they
do what we want. That being said, there needs to be A LOT of yeast to fully ferment
the beer. This means yeast starts, repitched yeast, or using multiple yeast packets. I
use www.mrmalty.com to help figure out how much yeast to add. Using multiple
yeast packets is easy but expensive. Repitching yeast works well if it is not stored
for more than a week or two. Yeast starters though are my preferred method.

My method for yeast starters is easy. 1 gram DME per 10 mL of water. If you are
making a 500 mL yeast starter, add 50 grams DME. Boil for 15 minutes, chill in an
ice bath, add yeast, let ferment. I use an erlimier flask that I can boil in on the stove
and I cover the top with tin foil for the duration of the boil to sanitize, I don’t use an
airlock. You want oxygen to be picked up in solution to keep the yeast multiplying as
much as possible.
No matter what vessel you use to ferment the yeast starter, you need to keep it
suspended in solution. This means swirling it up every so often or using a stir plate.
And finally, once the ferment is done on the starter, chill it down for a day or so,
pour off most of the liquid, then let warm back up to room temp. Swirl and add to
well oxygenated wort and let them do their magic.