A couple days ago someone posted a question on a forum about what would be considered the main factor in brewing beer, boiling time or temperature control. Basically the question was, “If you could only choose one or the other, which one would you choose to pay attention to?”

Time?

You can’t do anything about it… you just have to wait if you want better beer…

Temperature?

Temperature control is possibly the hardest task in brewing beer, yet the one that affects flavor the most.

Now honestly, I don’t know exactly what triggered this question, but… if you don’t have a fridge you basically have to figure out other ways to control your fermenting temperature. I’ve seen people wrap a wet towel around their buckets, and place a fan next to it to drop the temperature. Others will get a small bath and keep the bucket in the water (maybe add some ice to drop the temp as needed)…

The only reason why one should be anal about temperature is because again, it greatly influences flavor in beer…

But there is also another reason… as I explained in my blog post Beer Fermentation Temperature and Process, temperature also affects yeast behavior…

Here’s an email I got from a reader

>>>> Question >>>>

Hi Jorge,

I am pretty new at brewing so bear with me. I made a recipe from the
extreme brewing book Indian Brown Ale–It is and extract recipe very
easy to follow.

I started with a OG of 1.067 and left it in the primary
fermenter for 11 days (carboy). I checked gravity and it was 1.012
smelled great and a small sample tasted great. It was in the secondary
for 14 days and then bottled.

I made a 3 gallon batch instead of the 5
in the recipe and as such used 60% of the amounts in the recipe. This
included the priming sugar in the form of corn sugar (3 oz instead of
5).

I let the bottles sit for about 10 days and then put them in the
refrigerator to chill and waited another 2 weeks to drink.

The result was a very good smelling, flat beer. It tastes exactly as I
expected—just flat. All of the flavors come through and leaves a nice
taste on ones tongue. I have another 3 gallon batch in the secondary
now—what did I do wrong? And, more importantly, how can I avoid a
second wasted batch?

Martin

>>>> My Answer >>>>

I’m going to make many assumptions here, but here’s what I think more than likely happened…

One thing many brewers don’t realize is that beer has suspended yeast even if you rack it to a secondary fermenter and when you bottle it. In fact, unless you filter your beer  you will more than likely have a little bit of sediment in your beer bottles just like you get in your fermenter.

All that sediment is just yeast dropping out of suspension…

Now here’s what’s important to understand to fix this flat beer issue. When you add your priming sugar to your beer, you are essentially feeding the yeast. Just like you did by making your wort with DME which is basically a bunch of different sugars.

Yeast will eat that sugar and turn it into alcohol and CO2 both when fermenting and when you prime. When you are fermenting, the CO2 is released through the airlock. When you bottle, the CO2 stays in the bottle.

At first it goes into the headspace. As more CO2 starts to build up, the CO2 has two options 1) try to escape by pushing the cap off or making the bottle explode or 2) choose the path of least resistance and dissolve back into the liquid…

That’s essentially how a beer gets carbonated…

Now in your case, what happened was that you took your bottles and refrigerated them after 10 days when the yeast were not done turning the priming sugar into CO2. Remember, the behavior is pretty much the same as when you are fermenting.

What happens if you ferment an ale at 45-48 F?

Well, it doesn’t ferment… the yeast will go dormant below 60- 63 F (depending on the strain)….

The same thing happened with your bottles, the yeast went dormant before they produced enough CO2 and that’s the reason why the beer is flat. Now I’m sure, you’ll still get a bit of a hiss when you crack it open, but you don’t have the level of carbonation you are looking for.

You want to have your beer sit and bottle condition for 3 weeks at 70F in order to get all the CO2 produced and then refrigerated them for at least 24 hours…

In my Better Home Brew Formula Training, I go into detail how temperature affects the flavor of beer at different stages in the brewing process and how temperature affects carbonation as well as the amount of priming sugar you should be using.