Newbie SG/Yeast/Bottle Bomb Question

[RileyOG]

I have a batch of fortified cider that started out at 1.07 SG and finished off at 0.988 SG. (10.76 ABV by my calculation) I kept it in a 3 gallon carboy for 62 days and then bottled it in 32 oz swing-top bottles. I used Nottingham high performance ale yeast which I believe has a 14% ABV tolerance maximum.

22 days after bottling, I wanted to see if adding sugar to a bottle would create carbonation. I sampled the bottled cider, and it came out to 0.984 SG, (down .004 from the bottling). Despite a little bit of fermentation continuing, there was no noticeable carbonation in the bottled cider.

Question: how long will yeast remain active after it has gone past 0.99? If I add a small amount of sugar as a primer, will the yeast continue to work on it?

Yes, I know you have to be very careful and I am trying the plastic water bottle test first. After 10 hours, I popped the plastic to see if anything was happening and there was a noticeable "pop." (Not huge, but there..)

Any thoughts on this source as a priming calculator?

https://www.northernbrewer.com/pages/priming-sugar-calculator

 

[dmtaylor]

I'm having a hard time believing your specific gravity is below 0.990. I've made a lot of cider and mead and never seen a specific gravity below 0.992, and usually it's in the upper 0.99_'s. I wonder if your hydrometer is properly calibrated. Try floating it in plain water close to room temperature to see if it's reading at 1.000 or something else (likely too low).

22 days is not much time to carbonate a cider. Leave your bottles for a couple more weeks and by then you should have more carbonation.

The yeast will continue to work, but will be extremely sluggish from the 10% ABV. They are very tired.

I don't trust that priming sugar calculator at all, it's garbage. It will result in low to no carbonation. If you used that, it might explain undercarbonation even after waiting a couple more weeks (as I recommended initially above).

 

[RileyOG]

Thanks! I just took the attached picture in distilled water and it comes in at 0.992, which means -- what? -- my final SG should have been 0.996 (0.988+(1-0.992)). The meter is reading lower by 0.008, so add that to anything measured?

I should have been more clear in my original post. I bottled this extremely dry cider in 32 oz bottles for 22 days, and THEN (today) began experimenting with added primer.

 

[mac_1103]

22 days after bottling, I wanted to see if adding sugar to a bottle would create carbonation. I sampled the bottled cider, and it came out to 0.984 SG, (down .004 from the bottling). Despite a little bit of fermentation continuing, there was no noticeable carbonation in the bottled cider.

Just so we're clear - you bottled without priming sugar but now you'd like to try carbonating some of the bottles three weeks later?

First of all, I'm also a bit skeptical of your hydrometer readings. Mine only goes to 0.990. And if you really had dropped 4 points in the bottles then I think you would have noticeable carbonation. Four points is equivalent to a bit more than 0.3 ounces of corn sugar in 32 ounces, which according to my favorite carbonation calculator should give you over 3 volumes of CO2. So if your cider really is still fermenting in the bottles, then I think your swing tops must be leaking. So I'm going to assume that there has not in fact been any fermentation in the bottles.

If you want to try to carbonate now, I would suggest adding both priming sugar and a bottling yeast like CBC-1 or a wine yeast like EC-1118. I'm not going to tell you how much priming sugar because I have no idea how much fizz is good for ciders, but I will say that the calculator you linked does seem to err on the low side.

 

[mac_1103]

The meter is reading lower by 0.008, so add that to anything measured?

Correct. You may also need to correct for temperature.

 

[Zippy123]

I would suggest enjoying your still cider without risking oxidation and infection by trying to add things now. And start on your next batch of cider with the intention of carbonating some or all of it. If you wanted some still and some carbonated it would be much easier to split at bottling time, only adding priming sugar to the amount of the batch you wish to be carbonated. Or keg it with nitrogen for still and CO2 for carb.

The last time I made hard cider was before the turn of the century, in my early years of the hobby. I thought fermentation was fully complete and bottled it. The first few bottles were consumed within a few days and it was okay but obviously needed more rest. I didn't have any for about a month, but when I did I got a small surprise. Apparently it had not fully fermented out because it was now carbonated but to a very low and pleasant level. I have no idea where the SG sweet spot was in terms of natural carbonation, but the accidental carbonation came out perfect. Like winning the lottery twice, the odds of repeating that success are miniscule. Just sharing.

 

[RileyOG]

Just so we're clear - you bottled without priming sugar but now you'd like to try carbonating some of the bottles three weeks later?

First of all, I'm also a bit skeptical of your hydrometer readings. Mine only goes to 0.990. And if you really had dropped 4 points in the bottles then I think you would have noticeable carbonation. Four points is equivalent to a bit more than 0.3 ounces of corn sugar in 32 ounces, which according to my favorite carbonation calculator should give you over 3 volumes of CO2. So if your cider really is still fermenting in the bottles, then I think your swing tops must be leaking. So I'm going to assume that there has not in fact been any fermentation in the bottles.

If you want to try to carbonate now, I would suggest adding both priming sugar and a bottling yeast like CBC-1 or a wine yeast like EC-1118. I'm not going to tell you how much priming sugar because I have no idea how much fizz is good for ciders, but I will say that the calculator you linked does seem to err on the low side.

RE: "Just so we're clear - you bottled without priming sugar but now you'd like to try carbonating some of the bottles three weeks later?"

Yes.

As @dmtaylor observed, it looks like my hydrometer is off. It appears to register 0.008 lower than actual.

Nonetheless, the bottled cider appears to be very dry at 0.992 (false reading of 0.984 22 days after bottling plus 0.008 meter error).

Interesting that you both felt the primer calculations were very low. (I'm wondering if brewing supply houses are nervous about bottle explosion injury?)

The last time I let a cider go extremely dry, and then bottled it, I added 1/2 teaspoon of table sugar to a 22 ounce bottle of dry cider and the carbonation was pleasant.

I was just curious as to whether the yeast is "still there and working" even after you bottle it for 22 days.

 

[mac_1103]

I was just curious as to whether the yeast is "still there and working" even after you bottle it for 22 days.

My concern is the high ABV and the 84 days total. That's got to be some pretty worn out yeast at this point. I always add yeast when bottling beers that are over 9% ABV and/or have been bulk aged for several months.

 

[dmtaylor]

The last time I let a cider go extremely dry, and then bottled it, I added 1/2 teaspoon of table sugar to a 22 ounce bottle of dry cider and the carbonation was pleasant.

I was just curious as to whether the yeast is "still there and working" even after you bottle it for 22 days.

It's iffy. The yeast gets so tired with 10% ABV in there that it's a crapshoot. Half the time you'll get some carbonation after a couple months. Half the time you won't.

 

[RileyOG]

My concern is the high ABV and the 84 days total. That's got to be some pretty worn out yeast at this point. I always add yeast when bottling beers that are over 9% ABV and/or have been bulk aged for several months.

That's what I'm really getting at -- the probability of "worn out yeast." Even though my hydrometer was off, this yeast apparently kept working in the bottles, so I'm going to try adding very small amounts of primer and see if I can coax the remainder into bubbles.

Next batch, live and learn.

 

[mac_1103]

this yeast apparently kept working in the bottles,

Again, I'm very skeptical of that. Dropping four points in sealed bottles without getting any carbonation seems unlikely. When I add 5 ounces of priming sugar to 5 gallons of beer I'm only adding about 3 gravity points and I get around 2.5 volumes of CO2. Even if you decarbonated the cider before bottling you should have something like 1.6 to 1.7 volumes.

 

[RileyOG]

Dropping four points

At the risk of sounding dumb, when you say "points" on a hydrometer, with reference to SG, you are talking about "thousandths," right?

You are probably right. I will wait a few days on the plastic bottle test and see if the yeast did anything with the primer.

 

[mac_1103]

when you say "points" on a hydrometer, with reference to SG, you are talking about "thousandths," right?

Exactly. Common vernacular. It's just not possible to ferment from 0.996 to 0.992 without generating a noticeable amount of CO2.

 

[RileyOG]

At the risk of tiring everyone out, what is the highest SG you would risk bottling cider? Seems to me I remember 1.005 being mentioned in one of the cider recipe books.

 

[dmtaylor]

Bottle when the SG stops decreasing over the course of a week or two. If you get a reading of 0.999 and it's stable there for over a week without decreasing another thousandth, it's safe to bottle. Conversely, if you measure 0.997 and it goes down to 0.996 after a week, you shouldn't bottle yet. Wait at least another week, and when it steady, then it's safe. Same goes for 1.009, 1.005, anything else. Wait until the yeast is done... and then wait another week or two, then check again. When it's stable, it should be safe.

 

[RileyOG]

Bottle when the SG stops decreasing over the course of a week or two. If you get a reading of 0.999 and it's stable there for over a week without decreasing another thousandth, it's safe to bottle. Conversely, if you measure 0.997 and it goes down to 0.996 after a week, you shouldn't bottle yet. Wait at least another week, and when it steady, then it's safe. Same goes for 1.009, 1.005, anything else. Wait until the yeast is done... and then wait another week or two, then check again. When it's stable, it should be safe.

Thanks. That makes sense for a flat, dry cider, but if you want to bottle carbonate, it sounds like you could be in trouble, even if you waited for, like, 1.002, since it might make it down to 0.997.

 

[RileyOG]

Again, I'm very skeptical of that. Dropping four points in sealed bottles without getting any carbonation seems unlikely. When I add 5 ounces of priming sugar to 5 gallons of beer I'm only adding about 3 gravity points and I get around 2.5 volumes of CO2. Even if you decarbonated the cider before bottling you should have something like 1.6 to 1.7 volumes.

You were right. I used a 23.7 ounce plastic bottle and added 44 grams of table sugar. I let it sit for a week and there was no carbonation, although I didn't check SG.

I'm guessing that my hydrometer under-reporting SG by 8 points was what "worked" for me in the past. I must have thought 1.008 (actual) was 1.000, added 1/2 teaspoon sugar to 22 oz cider bottles, and achieved pleasant carbonation.

Do you know of a good priming calculator that indicates at what SG to bottle-sweeten and then pasteurize?

 

[Chalkyt]

Yes, trying to bottle condition and sweeten can be a bit of a mission.

Rather than worry about on-line priming calculators, I use an alternative approach of adding sugar to increase the SG above the FG to generate the sweetness and CO2 volumes that I want.

I don’t use a priming calculator because I find it is easier to go back to first principles and use SG as a guide to adding sugar. It makes life easier because you just have to make up a sugar syrup or juice or concentrate and add it into the bottling bucket until you reach the target SG increase. It results in even distribution of the sugar when bottling.

It works this way…

For carbonation, sugar ferments into 47% CO2 (plus 48% alcohol and 5% other compounds). CO2 has a density of 1.87g/L at 15C (a typical fermentation temperature for cider). So, the amount of sugar needed for a volume of CO2 (i.e. a litre of CO2 in a litre of cider) is 1.87g/L divided by 47% = 3.98 grams (near enough to 4 grams).

Specific gravity tables* for apple juice show that a change of one gravity point (SG 0.001) results from fermenting 2 grams of sugar per litre. So, fermenting 3.98 grams (say, 4 grams) of sugar will change the SG by two gravity points (0.002).

Also, this aligns with the often quoted “two teaspoons of sugar per litre” for bottle conditioning (2 gravity point = 4 grams of sugar x 2.5 volumes = 10 grams =2 teaspoons of sugar in a litre).

As a rule of thumb, fermenting 2 gravity points (4g/L of sugar per litre ) will result in one volume of CO2.

For sweetness, the cider needs residual unfermented sugar. As above, specific gravity tables* for apple juice show that one gravity point (SG 0.001) results from 2 grams of sugar per litre. Two teaspoons of sugar (10 grams) per litre is about the same sweetness as half a teaspoon of sugar in a cup of coffee, which is what I aim for in my sweeter ciders. So, 10 g/L of sugar accounts for 5 gravity points (SG 0.005). Incidentally this would be classified as something like medium-dry to medium under BJCP guidelines.

As a rule of thumb, 5 gravity points of residual sugar (10g/L of sugar per litre) will result in medium-dry to medium sweetness cider.

As an example, a litre of cider aiming to finish about medium dry with 2.5 volumes of CO2, needs to ferment 5 gravity points then be pasteurised to stop fermentation with 5 gravity points of residual sugar remaining for sweetness. This can be achieved by fully fermenting then adding sugar to start at SG 1.010 (20 g/L of sugar) or "on the way down" if you are confident about what the FG will be.

It is a bit of a “rough and ready” approach, but in practical terms the results are quite consistent for for my home craft cider.

*A note about specific gravity tables for apple juice…

If you look at a specific gravity table, you will see that some show that it takes 2.5 grams of “sugar” per litre to increase SG by 0.001. What they really mean is 2.5 grams of Total Solids, of which only 80% is sugar (the other 20% is non-fermentables like acids, tannins, etc).

So, if juice or juice concentrate is added to increase the SG, 2.5 grams per gravity point increase is correct. But if straight sugar is added (e.g. sugar syrup), the Total Solids figure needs to be discounted by 20% to 2 grams per gravity point or look at tables that show SG vs Sugar as well as Total Solids (Jolicoeur and Proulx & Nichols have such tables).

Have fun once your head stops spinning!

P.S. Alex Simmens of Llanblethian Orchards in Wales U.K. has written an excellent "Bottle Conditioned Cider Guide". I originally used the guide to develop the above approach. The guide covers the whole topic in much more detail, dealing with product style, bottles, yeast, sulphite, pasteurisation and trouble shooting. It is easiest accessed by Googling "Llanblethian Cider: Bottle Conditioning".

 

[RileyOG]

 

[RileyOG]

Yes, trying to bottle condition and sweeten can be a bit of a mission.

Rather than worry about on-line priming calculators, I use an alternative approach of adding sugar to increase the SG above the FG to generate the sweetness and CO2 volumes that I want.

I don’t use a priming calculator because I find it is easier to go back to first principles and use SG as a guide to adding sugar. It makes life easier because you just have to make up a sugar syrup or juice or concentrate and add it into the bottling bucket until you reach the target SG increase. It results in even distribution of the sugar when bottling.

It works this way…

For carbonation, sugar ferments into 47% CO2 (plus 48% alcohol and 5% other compounds). CO2 has a density of 1.87g/L at 15C (a typical fermentation temperature for cider). So, the amount of sugar needed for a volume of CO2 (i.e. a litre of CO2 in a litre of cider) is 1.87g/L divided by 47% = 3.98 grams (near enough to 4 grams).

Specific gravity tables* for apple juice show that a change of one gravity point (SG 0.001) results from fermenting 2 grams of sugar per litre. So, fermenting 3.98 grams (say, 4 grams) of sugar will change the SG by two gravity points (0.002).

Also, this aligns with the often quoted “two teaspoons of sugar per litre” for bottle conditioning (2 gravity point = 4 grams of sugar x 2.5 volumes = 10 grams =2 teaspoons of sugar in a litre).

As a rule of thumb, fermenting 2 gravity points (4g/L of sugar per litre ) will result in one volume of CO2.

For sweetness, the cider needs residual unfermented sugar. As above, specific gravity tables* for apple juice show that one gravity point (SG 0.001) results from 2 grams of sugar per litre. Two teaspoons of sugar (10 grams) per litre is about the same sweetness as half a teaspoon of sugar in a cup of coffee, which is what I aim for in my sweeter ciders. So, 10 g/L of sugar accounts for 5 gravity points (SG 0.005). Incidentally this would be classified as something like medium-dry to medium under BJCP guidelines.

As a rule of thumb, 5 gravity points of residual sugar (10g/L of sugar per litre) will result in medium-dry to medium sweetness cider.

As an example, a litre of cider aiming to finish about medium dry with 2.5 volumes of CO2, needs to ferment 5 gravity points then be pasteurised to stop fermentation with 5 gravity points of residual sugar remaining for sweetness. This can be achieved by fully fermenting then adding sugar to start at SG 1.010 (20 g/L of sugar) or "on the way down" if you are confident about what the FG will be.

It is a bit of a “rough and ready” approach, but in practical terms the results are quite consistent for for my home craft cider.

*A note about specific gravity tables for apple juice…

If you look at a specific gravity table, you will see that some show that it takes 2.5 grams of “sugar” per litre to increase SG by 0.001. What they really mean is 2.5 grams of Total Solids, of which only 80% is sugar (the other 20% is non-fermentables like acids, tannins, etc).

So, if juice or juice concentrate is added to increase the SG, 2.5 grams per gravity point increase is correct. But if straight sugar is added (e.g. sugar syrup), the Total Solids figure needs to be discounted by 20% to 2 grams per gravity point or look at tables that show SG vs Sugar as well as Total Solids (Jolicoeur and Proulx & Nichols have such tables).

Have fun once your head stops spinning!

P.S. Alex Simmens of Llanblethian Orchards in Wales U.K. has written an excellent "Bottle Conditioned Cider Guide". I originally used the guide to develop the above approach. The guide covers the whole topic in much more detail, dealing with product style, bottles, yeast, sulphite, pasteurisation and trouble shooting. It is easiest accessed by Googling "Llanblethian Cider: Bottle Conditioning".

Thank you for that detailed response. I will try to digest, because things seem confusing. (My degree was in history, not chemistry.)

It gets a little more confusing. When I was doing this test, I tried it on both a 23.7 oz plastic bottle and on a 32 oz swing top bottle. Since the plastic bottle didn't produce carbonation, I assumed the 32 oz bottle would not either, so I went into my cider brewing cave, and on a lark, shook the bottle and opened it. It was champagne on speed. I lost about 25% o the contents.


Reviewing..

Original brew..
3 gallon carboy.. 1/3 Granny Smith Cider, 2/3 Fuji Cider, 32 oz table sugar, 17.1 brix
61 days later, this batch was bottled in swing-top 32 oz bottles.. SG was 0.997
22 days later, SG was 0.992 with no visible carbonation after opening the bottles.
As a test, I added 2 teaspoons of sugar to one of these bottles
20 days after adding the sugar, and concluding no carbonation was taking place, I shook the bottle, and opened it, losing about 25% of the contents.
I am guessing a hydrometer doesn't work with carbonated brew, right? It looks like it measures 1.000

 

[Chalkyt]

Your two teaspoons of sugar have done exactly what they should.

Plastic bottles need to have the cap very tight or they can leak... even flip top bottles can leak above around 80psi. I have a Grolsch "test" bottle with a pressure gauge fitted to the cap so that I can monitor carbonation pressure as it progresses (it helps to choose the right time to pasteurise for carbonation and sweetness (i.e. about 2 bar or 30psi).

Once all the sugar has been turned into alcohol and CO2 the hydrometer should read around 1.000. Your pic looks a little above 1.000. Two possible reasons... there is still a little sugar left, or CO2 bubbles are sticking to the hydrometer making it more buoyant (you need to spin/dunk it a few times to get rid of them).

 

[mac_1103]

I have a Grolsch "test" bottle with a pressure gauge fitted to the cap so that I can monitor carbonation pressure as it progresses

Would love to see a pic of that bad boy.

 

[Chalkyt]

Here are pics of them in action today. It is quite straightforward to do...

1. Get a small pressure gauge (psi, bar, kPa). It doesn't really matter as long as you know what the pressure means. I found mine on eBay.
2. Get a screw on fitting to fit the gauge input. In the USA it is usually NPT (National Pressure Thread), although sometimes gauges have BSP (British Standard Pipe). You will need some teflon pipe thread tape to make sure the seal is good (or just epoxy it in place).
3. Find a metal thread screw that is smaller (but not too small) than the hole in the bottom of the fitting that the gauge screws into and cut the screw about 1/2" - 3/4" long. Drill a small hole up the middle of the screw and solder, braise, epoxy or whatever the screw into the gauge fitting. This is the path from inside the bottle to the gauge.
4. Drill and tap a hole in the top of a plastic Grolsch (flip top) cap part way down but not past where the wire bail holes are. This is to avoid drilling into the wire bails horizontal hole or through the side of the cap and creating a leak. There isn't a lot of room for error here.
5. Drill a small diameter hole from the bottom of the tapped hole through to the bottom of the Grolsch cap. (i.e. a continuous no-leaks hole all the way past the bail hole and through the cap)
6 Assemble the whole thing, sealing where the screw goes into the Grolsch cap with epoxy, silicone or whatever.
7. Put your conditioned cider into the Grolsch bottle and seal, then watch the carbonation pressure as it increases to whatever you want. The pressure in the Grolsch bottle should be the same as the pressure in the rest of the bottled batch.

A good guide to pressure vs volumes of CO2 is Andrew Lea's Carbonation Table (Google it or search his web site) which calculates pressure for given volumes of CO2 at a particular temperature (e.g. at 20C, 2.5 vol of CO2 will have a carbonation pressure of 1.86bar or 27psi, however if you are hot waterbath pasteurising to stop carbonation, at 65C, 2.5 vol of CO2 will have an in-bottle pressure of 7.5bar or 109psi. That is why I limit my waterbath pasteurising to 65C and 2.5 volumes of CO2 to avoid bottle-bombs. One of the advantages of this approach is that you can drink the test bottle "in the interest of science"!!!!!

There are other versions of this on HBT. Have Fun!

 

[An Ankoù]

Here are pics of them in action today. It is quite straightforward to do...

1. Get a small pressure gauge (psi, bar, kPa). It doesn't really matter as long as you know what the pressure means. I found mine on eBay.
2. Get a screw on fitting to fit the gauge input. In the USA it is usually NPT (National Pressure Thread), although sometimes gauges have BSP (British Standard Pipe). You will need some teflon pipe thread tape to make sure the seal is good (or just epoxy it in place).
3. Find a metal thread screw that is smaller (but not too small) than the hole in the bottom of the fitting that the gauge screws into and cut the screw about 1/2" - 3/4" long. Drill a small hole up the middle of the screw and solder, braise, epoxy or whatever the screw into the gauge fitting. This is the path from inside the bottle to the gauge.
4. Drill and tap a hole in the top of a plastic Grolsch (flip top) cap part way down but not past where the wire bail holes are. This is to avoid drilling into the wire bails horizontal hole or through the side of the cap and creating a leak. There isn't a lot of room for error here.
5. Drill a small diameter hole from the bottom of the tapped hole through to the bottom of the Grolsch cap. (i.e. a continuous no-leaks hole all the way past the bail hole and through the cap)
6 Assemble the whole thing, sealing where the screw goes into the Grolsch cap with epoxy, silicone or whatever.
7. Put your conditioned cider into the Grolsch bottle and seal, then watch the carbonation pressure as it increases to whatever you want. The pressure in the Grolsch bottle should be the same as the pressure in the rest of the bottled batch.

A good guide to pressure vs volumes of CO2 is Andrew Lea's Carbonation Table (Google it or search his web site) which calculates pressure for given volumes of CO2 at a particular temperature (e.g. at 20C, 2.5 vol of CO2 will have a carbonation pressure of 1.86bar or 27psi, however if you are hot waterbath pasteurising to stop carbonation, at 65C, 2.5 vol of CO2 will have an in-bottle pressure of 7.5bar or 109psi. That is why I limit my waterbath pasteurising to 65C and 2.5 volumes of CO2 to avoid bottle-bombs. One of the advantages of this approach is that you can drink the test bottle "in the interest of science"!!!!!

There are other versions of this on HBT. Have Fun!

Or you can buy one ready made.
https://braumarkt.com/Mattmill-Manometer-for-crowncap-bottles

 

[Chalkyt]

Thanks for that. It looks like a good product. Should be possible for someone to make a DIY version. Sadly, the vendor is EU based and the product isn't available here in Oz. At around $75AUD or $50USD it looks like a worthwhile addition to the war chest.