SABASTIAN DESOTELLE: Now that you have a
good grasp on the impacts of fermentation temperature, we're going to discuss how you
can actually control that temperature in that optimal range for your yeast,
to hit the flavor profiles you're looking for in your beer consistently.
There's a couple different ways to control the temperature, whether you're going from
high to low or low to high, and we'll give examples of each of these here,
and then with your own experience you can always expand upon these.
For a simple way to control the temperature, you can
find the temperature in your house that hits that optimal temperature range.
If you need to come up in temperature a little bit, you can use something
as simple as wrapping it in a blanket, or an electric blanket, or heat wrap of some kind.
If it's too warm in temperature, and you're looking at bringing it down a little bit,
you can do something, something called a swamp cooler is a good example.
Where you put your fermenter into a tub full of water,
wrap that in a towel that touches the water to wick some of that moisture up, and then put a
fan on it, that allows the water to evaporate and sink some of the heat from the fermenter.
Again a quick footnote for some of these simpler
and lo-fi efforts to maintain your fermentation temperature,
is they do take some monitoring because they do not self-monitor themselves.
With the swamp cooler, you're only going to get a couple degrees of change.
And with something like a blanket around your fermenter you're still at the mercy
of your yeast's metabolic rate changing in temperature over the course of fermentation.
So it is going to take some monitoring, of you,
to make sure that the the temperature is still in that optimal range.
A better way to control your temperature, would be something like a heat wrap or
the fermowrap, something you can wrap around your fermenter,
and that'll raise the temperature of your fermenter up 10 to 15 degrees from ambient.
Now typically speaking, if you're using something like a heat wrap you're going to want to use it
with a temperature controller of some kind, because those heat wraps are only on or off.
And so if you're only looking to raise it five, six, or seven degrees,
if you have it plugged in full time you're going to go too warm and get a little bit
too much of those phenolics and ester characteristics that we described before.
So having something like a temperature control,
which its sole purpose is just to turn it on and off based on temperature.
If you're looking to cool something down, and you want to step beyond that swamp cooler,
or that towel wrapped around there, what you can do, is you can do something like
a fridge or a chest freezer with that same control unit hooked up to it.
What that temperature controller does, it just tells your freezer to turn on and turn off.
So your freezer still thinks it's a freezer, but based on the temperature that you set it at it'll,
like a light switch [clicks tongue], turn on if it gets too warm,
[clicks tongue] turn off if it gets too cold.
Very simple, and does an amazing job controlling the temperature
consistently in the beer you're trying to make.
When you're using the Northern Brewer temperature controller,
it's got a temperature probe that reads the temperature, and you want that to read the
temperature of your fermentation, to either turn on your heat wrap or turn off your heat wrap, or
if you're cooling turn on your freezer or turn off your freezer.
A couple of different things that you can do with your temp probe is either attach it to the outside
of your fermenter with a piece of tape, and what I like to do is use a small piece of insulation
to go over that so it's reading as close to the fermentation inside of the fermenter as I can be.
The best way to do it is with a stopper thermowell.
And a stopper thermowell allows you to put the probe into the middle of the fermentation,
which is going to give you the most accurate reading of the actual fermentation.
When you look at the difference between the middle of your fermenter,
to the edges of your fermenter, you can have a variance of up to five
degrees in the total temperature just from the middle to the edge.
So if you want to get a very accurate reading of the actual temperature that's going on,
a stopper and thermowell will give you exactly that.
Still, simply taping the probe to the side of your fermenter will
be an effective way to get you very close to what that temperature might be.
For the most high-end way to control your fermentation temperature, there's companies
like Grainfather that produce a jacketed conical fermenter, that runs glycol through the jacket,
that'll maintain your fermentation temperature plus or minus a half a degree.
Now, you'd be looking at a couple thousand dollars for
investment in something like that, but it is going to do an amazing job consistently giving
you the beer that you want, and pushing you towards that commercial style brewing.
[Sabastian sighs] Okay, that was a
lot of information on temperature.
So let's do a quick recap.
One, fermentation temperature is important. If that's all you took out of this lesson, fantastic!
Two, there are different flavors that are produced at different temperatures,
and there's an optimal temperature range for your yeast.
So understanding what that optimal temperature range is,
then using a few of the techniques that we discussed to control it.
Either bringing your temperature down, which is the most common thing that you're going to be
doing, or trying to bring your temperature up, less common but still good information to know.
We could do an entire course discussing all the topics in this lesson, this was just a
basic overview really trying to emphasize the importance of fermentation temperature,
and the impact that it has on your beer, so that you can consistently make better beer.
Now there's a quiz following that will help you to make sure you understand some
of these topics before we move on, and we'll see in the next chapter.