Residual Sugars and Bottling---Must we add sugar?

[TheGrandYordle]

Hey there! So 2 weeks ago I brewed my first batch of beer using dry extracts. I plan on bottling (possibly tomorrow!) depending on what my final gravity reading is. However, from what I've read, it appears most people will add a "priming sugar" right before getting ready to bottle. The concern out there regarding final gravity is, if the residual sugar and the priming sugar combined is too great, then there could be bottle bombs. On the other hand, not having enough sugar can result in lack of carbonation in your finished product.

My question is (for my next batch), if I calculate how much residual sugar there would be say, 3 or 4 days prior to my final gravity reading, can those sugars be used to generate carbonation, thus eliminating the need to add a priming sugar altogether?

On an extension to that, does anyone do that now?

 

[flars]

When fermentation has gone to completion there are no residual sugars remaining the yeast can use for carbonation.

 

[hotspurdotus]

My question is (for my next batch), if I calculate how much residual sugar there would be say, 3 or 4 days prior to my final gravity reading, can those sugars be used to generate carbonation, thus eliminating the need to add a priming sugar altogether?

On an extension to that, does anyone do that now?

Would this would work? Yes.

Would I ever try it? No.

The problem is that final gravity can vary depending on a numbers of factors. Getting the expected carb level would be a crapshoot.

You'd also have to constantly check the SG of your beer. I try to open my fermenter as little as possible to avoid infection. And what if you reach your targeted SG in the middle of the night? Are you going to bottle then?

Adding priming sugar at bottling is easy and consistent. there's not much incentive to try what you're proposing.

 

[TheGrandYordle]

Right but what I'm saying is, what would happen if instead of fermenting completely, you fermented almost completely but allowed for residual sugars? Say hypothetically it takes 8 days for fermentation to complete. Can you bottle it 1 day sooner when the final gravity is slightly higher than what is expected after fermentation is complete, allowing it to finish fermentation in bottle?

 

[botigol]

What flars said. To your question, yes, you can bottle before fermentation is complete in order that the final bit of fermentation carbonates the bottles. I read that German brewer's did exactly that, but I do not recall the timeframe. However, I would think that extra caution should be exercised in this practice unless you are 100% certain of your calculations and the results that would come from them.

 

[boydster]

If you take 2 gravity readings over a 3 day period, you will know whether the yeast has consumed all of the fermentable sugars or not. If the 2nd reading is lower than the first, wait a little longer before bottling. If the readings match, you can bottle it up with your priming sugar and there will be no worrying about whether you are overcarbonating your beer.

Trying to get your beer into bottles at exactly the right time for it to carb properly (it would be with ~3 gravity points still to drop) is tough to do. Usually, a recipe has a target FG but you may find the actual FG is a couple points higher or lower. Other variables like temperature, pitch rate, yeast health, and the number of times you have harvested and repitched a particular yeast colony will also be a factor. Given the danger of exploding glass bottles, and the disappointment of drinking flat beer, the safest and most dependable solution is to ferment to completion and then prime with with sugar (or DME, honey, etc) to hit your target CO2 level.

Edit: Damn, you guys are fast

 

[TheGrandYordle]

Would this would work? Yes.

Would I ever try it? No.

The problem is that final gravity can vary depending on a numbers of factors. Getting the expected carb level would be a crapshoot.

You'd also have to constantly check the SG of your beer. I try to open my fermenter as little as possible to avoid infection. And what if you reach your targeted SG in the middle of the night? Are you going to bottle then?

Adding priming sugar at bottling is easy and consistent. there's not much incentive to try what you're proposing.

Ah ok. So it's probably just too risky and labor intensive on top of that to get it at that exact stage. That makes sense. I didn't really understand the concept behind the priming sugar over residual sugars until now...lol.

 

[beergolf]

Right but what I'm saying is, what would happen if instead of fermenting completely, you fermented almost completely but allowed for residual sugars? Say hypothetically it takes 8 days for fermentation to complete. Can you bottle it 1 day sooner when the final gravity is slightly higher than what is expected after fermentation is complete, allowing it to finish fermentation in bottle?

Unfortunately that will not work for a couple of reasons. One, yeast does not punch a time clock, so you have no way of knowing just how much fermentavle sugar is left. Two, estimated FG is just that, an estimate. For example a recipe says the Fg will be 1.010, but you mashed a little low and the real FG ends up at 1.006. What would happen? Bottle bombs.

Just let it go until it is done and then prime with the correct amount of sugar.

 

[mrphillips]

Everything that's been said is, well...what I was gunna say. BUT I will add that sometimes when a bucket is disturbed (i.e. - moving your bucket from one room to another for bottling), the yeast "wakes up," and can take a 1.012 down to 1.008 or lower in the bottle. That, plus whatever priming sugar you added, will make for a bad day sooner than later. TRUST ME.

 

[flars]

Right but what I'm saying is, what would happen if instead of fermenting completely, you fermented almost completely but allowed for residual sugars? Say hypothetically it takes 8 days for fermentation to complete. Can you bottle it 1 day sooner when the final gravity is slightly higher than what is expected after fermentation is complete, allowing it to finish fermentation in bottle?

Well, I guess it is possible. You could also calculate the odds on how far the glass shards might fly based on temperature, thickness of the bottle, how many times it has been stressed, and relative humidity.

FG has so many variables it cannot be predicted. It can only be measured after it has happened.

 

[jtratcliff]

FG has so many variables it cannot be predicted. It can only be measured after it has happened.

Quoted for truth!