Fast Fermentation

[Russ1409]

Hi all;

I've noticed that my fermentation is taking a lot shorter time than what is given on my recipes. The last two brews were supposed to take two weeks. At 9 days the FG was within the range.

This time I'm brewing a raspberry wheat. The SG was right in the range (1.042-1.046). The FG range is 1.012-1.017. Today, after just under 7 days, the FG was 1.008. My temperature is on the high side but not out of range (74 the first couple of days, down to 72 F right now).

Q1. What could be causing my brews to ferment up to twice as fast as the recipe calls for?

Q2. What is this going to do to the beer? The first batch was excellent. The second was poor do to a mistake in carbonation. This beer seems very, very tasteless...but of course it's a raspberry so maybe it shouldn't have much taste until the extract is added?

Tomorrow I will bottle it and in a couple weeks try it out.

Thanks,
Russ

 

[CA_Mouse]

This time I'm brewing a raspberry wheat. The SG was right in the range (1.042-1.046). The FG range is 1.012-1.017. Today, after just under 7 days, the FG was 1.008. My temperature is on the high side but not out of range (74 the first couple of days, down to 72 F right now).

Q1. What could be causing my brews to ferment up to twice as fast as the recipe calls for?

Is that temperature reading ambient temperature or the actual temperature of the liquid in your fermenter? If that is ambient, your fermenter temperature could be as high as 10* higher then that. This will cause a faster fermentation period. It could lead to off flavors, but isn't always apparent for a few weeks after bottling/kegging. I always shoot for 5*F lower than the lower temperature range for the yeast I'm using to compensate for fermentation temperature rise, then let the temperature free rise to the upper end after 10 days to allow the yeast to finish off any remaining sugars they can and to clean up any off flavors.

Q2. What is this going to do to the beer? The first batch was excellent. The second was poor do to a mistake in carbonation. This beer seems very, very tasteless...but of course it's a raspberry so maybe it shouldn't have much taste until the extract is added?

Tomorrow I will bottle it and in a couple weeks try it out.

Thanks,
Russ

Personally, I find most extracts that you buy at an LHBS leave a medicinal and/or fake flavor (think imitation vanilla vs. real vanilla). There are natural extracts that you can find on Amazon (a little pricey) that are a true fruit extract.

 

[Erik_Mog]

Higher temps can cause the yeast to be more active and ferment faster, but also run the risk of developing off flavors. That being said, for normal gravity beers, primary fermentation does not usually take but a few days. My last was a 1.053 Wheat that reached final gravity in 5 days. The additional time given for the fermentation is to allow the yeast to clean up byproducts of fermentation. You should leave the beer in the fermenter for 2-3 weeks to allow the yeast to do it's cleanup. If you have reached final gravity, and it had been stable for a couple of days, it wont hurt anything to bottle it, but letting it go for at least 2 weeks before bottling lets the yeast finish up.

 

[stonebrewer]

Fermentation has a lot of variables in it. Do you control your fermentation temps? Do you have a thermowell? If not, as the prior poster said you are guessing at one of the more important aspects of brewing: fermentation temperature. Yeast health and count can greatly affect the rate at which it converts sugar to alcohol. The type of sugar in your wort also plays a role. I find that most recipes call for a fermentation period that is longer than is actually needed. A lot of folks go from grain to glass in a week, even less. The yeast do "clean up" the beer, so some think it is better to leave the beer in the fermenter for 2 or more weeks. That is not always because they want the FG to go down, but instead is for that cleanup process. You are probably just fine, you made beer. Drink it, and if you like it, brew it again. You will get better at it over time and will improve your beer too. Cheers!

 

[Chris_Primavera]

A1. The recipe is giving a worst-case scenario. Depending on your yeast and pitch rate, fermenting a moderate OG batch like this could be done in 26-36 hours. Your temperature sounds high - which will also speed up the process but could lead to some off flavors. Are you measuring ambient or wort temperature? (Wort can be +5 to +10°F from ambient)

A2. High temperatures will yield more esters (apple, banana) and phenols (clove), and higher amounts of fusel and wood alcohols, as well as diacetyl (butter, butterscotch).

 

[Russ1409]

Thank you for the answers, everyone. I am not measuring the temperature of the wort. I have one of the stick on "starter kit" thermometers on the side of the glass chorboy. I'll start measuring the temperature of the wort itself.

 

[kh54s10]

Hi all;

I've noticed that my fermentation is taking a lot shorter time than what is given on my recipes. The last two brews were supposed to take two weeks. At 9 days the FG was within the range.

This time I'm brewing a raspberry wheat. The SG was right in the range (1.042-1.046). The FG range is 1.012-1.017. Today, after just under 7 days, the FG was 1.008. My temperature is on the high side but not out of range (74 the first couple of days, down to 72 F right now).

Q1. What could be causing my brews to ferment up to twice as fast as the recipe calls for?

Q2. What is this going to do to the beer? The first batch was excellent. The second was poor do to a mistake in carbonation. This beer seems very, very tasteless...but of course it's a raspberry so maybe it shouldn't have much taste until the extract is added?

Tomorrow I will bottle it and in a couple weeks try it out.

Thanks,
Russ

For recipes they allow plenty of time for the fermentation and for the yeast to totally finish. I do all my fermentations for 2 weeks and sometimes longer. Often just because of not getting around to packaging.

Warmer temperatures will speed the fermentation, not always good.

I ferment most ales in the mid sixties. Fermentation creates heat, so if room temperature is 70 degrees the wort may reach as much as 80 degrees which is likely to give off flavors, maybe even bad.

I don't know what you mean by the flavor is tasteless but maybe it shouldn't until extract is added?? Extract should be added and fermentation done before adding fruit, in most cases.

Typical fermentations last 3-7 days. Fermentation itself creates so bad flavors and the yeast will continue working on the wort and clearing these up. So you allow them to work for a few days longer.

So, your fermentations are not finishing twice as fast as they should. You are just rushing what the instructions are allowing for.

 

[kh54s10]

Thank you for the answers, everyone. I am not measuring the temperature of the wort. I have one of the stick on "starter kit" thermometers on the side of the glass chorboy. I'll start measuring the temperature of the wort itself.

These stick on thermometers are fairly accurate and is giving you the temperature of the wort. If in question think that it is a couple of degrees high. So cool a bit lower.

I would not try to measure the wort by opening the fermenter and using a thermometer in the wort. This could cause problems, either oxidation or infection. Use the fermometer strip.