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| Wine making kits, turbo yeast, beer : Tips : Home Brewing : Stuck fermentations |
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Stuck fermentations |
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If your fermentation has stuck and your wine is too sweet, here are some reasons that could have happened:
The yeast cells in your sachets have a limited life, a certain number dies every month and after 1-2 years there are very few viable cells left which means fermentation will not start properly. Check best before date! What can you do about it?
Heat will kill yeast cells. Try to keep liquid temperature below 30-35 C in the start unless instruction says otherwise. What can you do about it?
If air can get into the yeast sachet, yeast death will accelerate. Your wine yeast could be dead long before the best before date. Do you remember if the sachet seemed damaged, yeast leaking in the wine kit box etc? What can you do about it?
If you add wine yeast directly to grape concentrate, the osmotic pressure will harm the yeast cells. It is the same effect you can feel when diving deep into water - the pressure will harm your body if you get down deep enough. What can you do about it?
If you have below 18 C in your room, fermentation may often stick a bit premature and it will stick higher if temperature is even lower. It may be a few units on your hydrometer, say final value 1000 instead of 997. Large temperature changes increases this problem. What can you do about it?
These are manufacturing errors and not very common. In most cases there is not much you can do about it and it is unfortunately very difficult to separate these problems from the "normal" ones above. The only simple indication is if it seems as if many customers buying this wine kit have had similar problems. What can you do about it?It is not obvious that you should just add another wine yeast sachet. If fermentation has been going on for some time, there is alcohol in the wine kit. Yeast cells can only survive in alcohol if the level is moderate and if they gradually adapted to the alcohol level. So if you just add another yeast sachet it is very likely that the yeast will die. Check with a hydrometer - if the reading is close to the normal start value for your wine kit (if you have no clue, assume start value 1080) it means fermentation has not been going for long. That of course means low alcohol so in this case you can add a new yeast sachet. If the hydrometer reading is 50-60 units below the start value (i.e. 6-8% alcohol) you must use a special restart yeast. Willes Restart Superyeast will do the trick here. A normal wine kit starts at 1075-1085 so if your current reading is somewhere between 1015-1065 it is worth a try with this yeast. If your wine kit fermented most of the way and then stuck a little too soon (hydrometer reading 1000 or just over) you can normally not start it again. Try diluting it with 10% water, that will make it less sweet but unfortunately it will also lower the body and alcohol so don't overdo it. This trick works best with white wines where the body is not as critical as with reds. You can also increase the acidity slightly. This will mask some sweetness. Add 4-5 g of citric acid to a normal wine kit (20-25 litres), repeat if necessary but be careful and taste in between - you can not go back! |
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Copyright 2005 Hambleton Bard Ltd. (c2005-1) Legal Disclaimer: Should any of the advice given here on this site be illegal in your country of residence, you must not follow it. You are adviced to investigate the legal status of making your own alcohol - wine, beer and spirit (moonshine) and only follow the advice where legal. Should any of the advice or procedures given here on this site, require a special license, permit etc - you are responsible for acquiring such license, permit etc before proceeding with making moonshine, wine making or beermaking or any other activity listed or given advice on here. |
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