Apple cider isn't fermenting?

[Yuradex]

I started last fermenting apple cider and ginger ale using ginger bug as a starter.
It's been 7 days and while seeing a clear SG change on the ginger ale (that started at 1.061), the apple cider seems to be stack at 1.065 (it is now 1.064 but it's a small change that I don't think I should consider) for a week now. The jar looks like fermenting, there is light foam on top, but it isn't carbonated at all, and I wondered if I wonder if those bubbles on top are actually from fermentation.
I started fermenting both on the same day and used the same amount of starter per liter.

 

[bernardsmith]

Hi Yuradex and welcome to this forum.
What apple juice are you fermenting? Many store bought apple juices that are not clear have been processed with sorbates to prevent self-fermentation. That compound prevents yeast from reproducing and so essentially inhibits fermentation. Are you perhaps using a commercially pressed apple juice and does it perhaps list sorbates as a preservative? If so, you are stuck! Your juice will not ferment in any simple way. You may need to add 5 or 6 packs of yeast to neutralize the preservatives and most seasoned wine makers simply drink this juice and call it a day. Look for pressed juice without preservatives.

 

[Yuradex]

Hi Yuradex and welcome to this forum.
What apple juice are you fermenting? Many store bought apple juices that are not clear have been processed with sorbates to prevent self-fermentation. That compound prevents yeast from reproducing and so essentially inhibits fermentation. Are you perhaps using a commercially pressed apple juice and does it perhaps list sorbates as a preservative? If so, you are stuck! Your juice will not ferment in any simple way. You may need to add 5 or 6 packs of yeast to neutralize the preservatives and most seasoned wine makers simply drink this juice and call it a day. Look for pressed juice without preservatives.

Hey bernardsmoth, I got my juice from bio supermarket, and the bottle stated 100% apple juice, there isn't any ingredients list on the bottle but only the 100% lable. Temperature here is 15-25 degrees centigrade, so I assume it isn't the issue either. Should I try adding more starter? As I mentioned I used ginger bug, about 1 cup per 4L (around 1 gallon).

 

[bernardsmith]

If there is no preservatives in the juice then the problem might be using the ginger "bug" as the basis for fermentation. Certainly pressed apple juice will naturally self-ferment because of indigenous yeast on the apples and on the pressing equipment but the "bug" may have more lactobacteria than yeast and the acidity of the apple juice may inhibit any fermentation afforded by the ginger bug. You may want to either allow the juice to stand for a few more days to see what happens or you may want to look for a lab cultured wine yeast to kick start the fermentation.

 

[Yuradex]

If there is no preservatives in the juice then the problem might be using the ginger "bug" as the basis for fermentation. Certainly pressed apple juice will naturally self-ferment because of indigenous yeast on the apples and on the pressing equipment but the "bug" may have more lactobacteria than yeast and the acidity of the apple juice may inhibit any fermentation afforded by the ginger bug. You may want to either allow the juice to stand for a few more days to see what happens or you may want to look for a lab cultured wine yeast to kick start the fermentation.

I must admit I am confused
During the week I mixed my jar a couple of times and there was hardly any signs of fermentation, now it looks like in the picture, it seems something is going on in there, I wonder if I should add yeast or give it few more days, because that is a bigger change than I saw since I started.

 

[bernardsmith]

The only useful way to know what is going on is to measure changes in the specific gravity (density) of the liquid. Alcohol is less dense than water and the more sugar there is the more dense the liquid is so when yeast is fermenting sugar and producing alcohol (and CO2) the density (or specific gravity) drops. If you monitor the change in specific gravity using an hydrometer you can observe the fall in gravity and as the gravity approaches 1.000 you know that your yeast is fermenting actively and when at around 1.000 or below (eg .996) the specific gravity remains rock steady over a week or so then you know that either the yeast have quit or there is no more sugar that they can ferment. If significantly above 1.000 and the gravity is rock steady then you know there is a problem.

Hydrometers are glass tubes with a weight on one end and a scale that gives you a reading of how dense a liquid is in relation to pure water, where water is given a nominal density of 1.000. The more dense the liquid the higher the hydrometer floats, the less dense the liquid the lower it floats. In the US they cost about $10.

 

[Yuradex]

The only useful way to know what is going on is to measure changes in the specific gravity (density) of the liquid. Alcohol is less dense than water and the more sugar there is the more dense the liquid is so when yeast is fermenting sugar and producing alcohol (and CO2) the density (or specific gravity) drops. If you monitor the change in specific gravity using an hydrometer you can observe the fall in gravity and as the gravity approaches 1.000 you know that your yeast is fermenting actively and when at around 1.000 or below (eg .996) the specific gravity remains rock steady over a week or so then you know that either the yeast have quit or there is no more sugar that they can ferment. If significantly above 1.000 and the gravity is rock steady then you know there is a problem.

Hydrometers are glass tubes with a weight on one end and a scale that gives you a reading of how dense a liquid is in relation to pure water, where water is given a nominal density of 1.000. The more dense the liquid the higher the hydrometer floats, the less dense the liquid the lower it floats. In the US they cost about $10.

I am actually quite surprised because for a week there was completely nothing going on in the jar, and since posting this thread 15 hours ago, I wad just about to add more yeast and noticed the foam and some carbonation bubbles in the cider. I ended up changing nothing and I would leave it for a few more days. Idk what triggered it, but it seems like there was some major change in the jar and it started fermenting.

I am checking my SG with a refractometer, I know it isn't the most accurate tool, but I prefer to use a few drops over a whole tube.

 

[bernardsmith]

Refractometers are designed to work with light being refracted through water. When alcohol is present light is not bent the same way so any reading in the presence of alcohol tells you nothing unless you are applying a number of other calculations to account for the different refractive index of light through alcohol (and as your wine becomes more alcoholic so there is more alcohol in solution and so the calculations need to take account of that.
That said, if you use good sanitization practices you can always return the sample you took for an hydrometer reading. Wine ain't beer and wine is not as sensitive to spoilage organisms as beer (wine has more alcohol than beer, is more acidic and is not a haven for lactic bacteria in the way that wort and beer is).

Last thought: after a few days the colony of yeast will have grown and you could see what looks like a sudden burst of activity even with no action on your part.