If the gravity reading is stable for 2 days, between 990- 1.000 for wine I would suggest1. How do I know when primary fermentation has finish - one batch the HTW one was bubbling away when I bottled it the other mix off a BBC website wasn't really doing a great deal.
If you can let the primary fermentation complete (The fizzing to stop) and add additional sugars for the secondary carbonation. This does mean however you should limit the amount of alcohol produced in the primary fermentation of your wine to around 12% max, else the brew will have too high an alcohol content and the yeast will not be able to convert the additional sugar to give the fizz you want. Do you not use an airlock to monitor fermentation2. On subsequent batches should I wait for all the fizzing to finish before bottling.
YES3. Also the do you think I have a ticking time bomb with the HTW batch in sparkling wine bottles seeing as I'm letting off the pressure in the PET bottle twice a day at the moment?
Not by chilling, that will not work as it will only slow the fermentation down and not kill the yeast. You need to kill the yeast with sulphates or let the fermentation complete. Once you have measured the specific gravity of your still fermenting brew it will be easier to advise. At this point you have an unknown gravity and so we do not know how far it has dropped from its original gravity (Not that we will really ever know this) and how far it may be expected to fall to its final gravity. We need a Gravity reading to assist or else you should wait till the fizzing has stopped and then add a little more sugar when you bottle.4. Should I be trying to stop the fermentation by chilling avoiding exploding bottles?
You are probably on one of the best sites for advise already. Just read the forum posts and if it doesn't make sense ask a question5. Any other web reading you would recommend for idiots like me!!
Best advise I can give you at the moment is
1.Buy a hydrometer and sample flask.
2. Note the full details your recipe on any subsequent brew.
3.Take a gravity measurement of said brew before adding any yeast and write it down. (This reading will also tell you what % alcohol you can expect).
4. You can monitor by use of an airlock fermentation progress.
5. After 5 days take another gravity reading to monitor how well the yeast is converting the sugar into alcohol. Is it at bottling gravity (shown on most beer and wine Hydrometers)
6. If not leave for a little longer (around 2 days depending on expected Specific Gravity). and repeat step 5 until you get the same reading twice.
7. If you want fizzy wine you can now safely add some more sugar 5-10gms per 750ml bottle and bottle your brew.
I'm not saying you will not get bottle bombs with this method, but it will greatly reduce the risk and if you ever get one it will be because of a fault in the PET or glass bottle used, not because you have over pressurised your bottles. I have not had a broken bottle yet but then my beer is only lightly carbonated as I don't like or drink fizzy pop.
