Ask Mr. Wizard

Brewing While Camping


Gabe Smoley • Spokane, Washington asks,

I would like to start brewing small batches of beer while I am camping. I have most of the logistics figured out: set up camp next to a fresh water source, filter 1+ gallons, collect any local ingredients (e.g. blueberries), sleep, wake up and pack my campsite, brew a 1–gallon (3.8 L) extract recipe on a portable jetboil stove, filter into a jug and hike out. My question is, when should I pitch my yeast? I figure the hike out will aerate the wort but how much time (and movement of the wort) is too much?


I love the adventurous spirit of the West. Add this to the reflex
for creative thinking common to homebrewers and out comes Gabe’s Nuts
and Berries Trail Ale. I must admit that this idea sounds like a
relaxing start to a day in the woods and, as long as you don’t have any
grand plans to turn this into an all-grain endeavor, it should be
fairly easy.

No matter the type of beer being brewed, which
relies on the introduction of yeast for fermentation (contrasting with
beers like lambic that are inoculated with yeast and bacteria from the
local area), it is extremely important to recognize the difference
between the hot and cold sides of the brewing process. The hot side
involves everything up to wort cooling and is notable with respect to
sanitation because the penultimate step is usually wort boiling. The
cold side involves handling cool wort and beer, both very good media
for the growth of microorganisms, and success in the cold side of
brewing really demands a clean and cleanable environment. The mountain
trails around Spokane do not come to mind when I think of a cold cellar.

Wort boiling can correctly be referred to as a process that achieves
commercial sterility, the semantics I will leave for personal research.
In commercial breweries it is common to move the wort from the kettle
to a whirlpool vessel before wort cooling and the hot wort is a form of
sanitizer for the whirlpool, explaining why whirlpools, unlike
fermentation vessels, are usually not sanitized after cleaning. Freshly
boiled, scalding hot wort is not likely to become contaminated from the
environment and wort contamination normally occurs during or after the
wort chilling process. Wort cooling really does two things for beer.
The most obvious achievement is that cooling permits the addition of
yeast to the wort and subsequent transformation of wort into beer.
Chilling also stops some of the chemical changes that happen to wort
when it is hot, such as color development, conversion of
S-methyl-methionine (SMM) to dimethyl sulfide (DMS) and isomerization
of alpha acids into iso-alpha acids. The general rule is to cool wort
quickly after boiling.

If I were serious about brewing out in the woods, I would disregard
the rule about rapid cooling and take a lesson from the treatment of
whirlpools before use. If you transfer your freshly boiled wort to a
1-gallon (3.8 L), heat resistant container that can be sealed, you are
doing what food processors call “hot filling” the container. The hot
fill process sanitizes the container with the heat of the product and
is a common method of filling a variety of food packages. After hot
filling you can then cool the wort to stop the reactions mentioned
above. The one reaction I am most concerned about when holding hot wort
after boiling is the transformation of SMM to DMS. You can use the
fresh water source near your campsite to cool your hot-filled container
of wort.

I wouldn’t be too concerned about precise temperature
control, just knock the wort temperature down below about 120 ˚F (49
°C) to prevent DMS formation, which really is more of an all-grain
concern because during the production of malt extract most of the SMM
in malt is converted to DMS and removed. But cooling the wort down also
will make your hike out a bit more comfortable since you won’t have a
jug of hot wort strapped to your back! On your hike out I wouldn’t
spend any time thinking about wort aeration because you really won’t
have much of that happening if you follow my plan. You want the wort to
remain commercially sterile after boiling. This will not happen if you
aerate the wort because you would need to get air into your jug. You
may get some air into the wort from the headspace, but hot filling
works best when you minimize the headspace so aeration ideally will not
happen on the hike out.

If you make it out of the woods, are able to avoid rush hour traffic
and get back home within 2–3 hours, you probably will be successful in
your endeavor. All you need to do is sanitize the outside of your jug.
You also need to sanitize a fermenter and ready your yeast. After
transferring the wort from transport vessel to fermenter, you will want
to aerate, then pitch your yeast and carry on as usual. Some readers
may be thinking I am reckless in my advice and that the best advice
would be to tell you to take your idea for a hike! However, there is
precedent for delaying yeast pitching in the method of trub removal
called flotation. So for all of those opposed to Gabe’s somewhat zany
idea, read up on wort flotation tanks and you will find some
similarities in the methods.

Response by Ashton Lewis.