If You Think Your Wine or Beer is Not Fermenting or You Think it Might be Ruined, Read This Homebrew Blog Post First.
Have you ever had a glitch when brewing?
We get lots of messages asking us for help, which normally cover the same concerns, so here are some tips that might reassure you that in the majority of cases, everything is fine and your brew will turn out well.
1 - Just because you have not seen anything happening with your brew, that does not mean it has not been fermenting.
Simply use a hydrometer to take a hydrometer reading and compare this to the one you took before you added the yeast. It’s most probably dropped. Check it again 24 hours later and you’ll probably find it’s dropped again if it hasn’t already finished fermenting that is.
It might be dropping slowly, so check your temperature (see number 2).
If it doesn’t move in 3 days, then it could be finished or even stuck. This is usually due to one of the following reasons, so read on to make sure you have done everything right. We’ll get to stuck fermentations at the end.
2 - Temperature is key. Just because your room thermostat says its 20°C, it doesn’t mean your fermentation is.
Stick an LCD thermometer to the side of your brewing vessel and keep it between 18-22°C to get the best results with most brews.
Try and keep the temperature constant. A changing temperature can cause the yeast stress and slow the fermentation.
To high or too low a temperature can cause your fermentation to stall.
3 - If you think your airlock should be bubbling away but it’s not, then there are a couple of things to check.
3a - Do you have an airtight seal
3b - Has it finished fermenting? See point 1 above.
3c - You may have too much water in your airlock. This can cause pressure to build up and the cause the gas to escape from somewhere easier.
4 - If your brew smells funky, it is probably NOT infected if you have sterilised anything that comes into contact with your brew.
It’s more likely that the yeast are turning phenols and acids in your brew to new compounds.
Be patient and give it time for the yeast to finish their work. Yeast don't just eat sugar. They have a varied diet and eat lots of other compounds in the fermentation. They then excrete these as new compounds / acids. These in time will combine with our compounds and acids to make new compounds. So there might be times in the brewing process that there are interesting aromas, but these will change over time as the wine/beer/cider conditions.
Red wines when young can smell like vinegar. Bottle them and let them age for 6-12 months. The vinegar aromas will mellow.
5 - Follow the instructions. If you are making a kit, read the instructions carefully. If your kit says do “x” on day “y”, there is usually a caveat saying as long as the S.G. is #.###. Make sure you measure your brew with a hydrometer and only move on to the next step if your hydrometer reading matches the instructions.
6 – Timing is everything. If you are following a recipe or instructions and they say to wait a certain time before moving on, then even if your hydrometer reading matches the instructions early, wait! Don’t be tempted to rush.
There are processes taking place that are crucial to the flavour. Yeast don’t just eat sugar. They can convert other compounds to add flavour and get rid of off flavours (see number 4).
7 - Time is key again. Sometimes, especially with wine, at the time of bottling, your wine can be very tart, dry, acidic, sweet or even bitter.
Bottle it and give it time for the wine to condition - see #4. Sometimes it takes a while for compounds to combine to make your wine, cider, beer or lager more enjoyable.
Over time, in the bottle, again, compounds will change with age and the flavour will develop. What was a sharp, tart wine at bottling can turn into a smooth wine with a nice acidic finish that makes your mouth water.
8 - Keep notes. This will help you when you come to make it again. Update your recipe notes with tasting notes so you can make adjustments to your brew next time you make it. Or in some cases, my book has recipes crossed through with the words “Never Again!”
9 - A clear brew. Did you know that you can drink a cloudy brew. There are a few things that can make a brew cloudy and they aren’t harmful, can actually add flavour and colour.
Let start with what can cause a haze. It could be...
a - yeast - these will eventually settle to leave a clear brew.
b - bits of fruit - these will eventually settle to leave a clear brew. Think cloudy cider mmmmmmmm!
c - pectin - will not clear without an enzyme to break down the pectin.
d - starch - will clear eventually but can be sped up with an enzyme.
e - protein - very hard to clear and is typical with wheat & craft beers
f - lupulin - from hops, adds a yellowness to a beer and lots of flavour so do you really want to get rid of it?
So you want your brew to be clear...
Have patience! All wine will eventually clear (if you give it enough time) but some due to the fruit, can take months to clear where others take just a few weeks.
You can speed up the clearing process by using finings. These cause particles to clump together and sink to the bottom.
When clearing, make sure your brew is below 15°C to help speed up the process.
10 - Sometimes a brew can get stuck, and there are usually a few reasons...
a - the wrong yeast. Not all yeast can tolerate high levels of alcohol. Use the right yeast for your brew. It’s highly unlikely the yeast in a packet will be at fault. The best before date means that there are still 50% of the yeast still ready to go. And just 1 live yeast, given time will divide into billions.
b - unfermentable sugars. In beer there are some complex sugars that yeast can’t eat. This is what gives beer it’s slight sweetness. It may appear stuck when it has actually finished fermenting.
c - not enough dissolved oxygen in the water. Normally associated when brewing beer from grain due to the boiling process as that can knock out the oxygen from the water. Just like fish, yeast need oxygen too. Remember to aerate your wort at the beginning, before pitching your yeast. Do not aerate your wine or beer once fermentation has begun.
d - not enough nutrients. Like us, yeast struggle if they don’t have the right vitamins.
e - Temperature. Fluctuating, too high or too cold will cause a fermentation to stall. It can even kill the yeast.
A Stuck Fermentation
First check if your brew is really stuck with a hydrometer, as it may have already finished fermenting. Take a note of the reading.
If the hydrometer is showing there is unfermented sugar (remember that beer will always have some non-fermentable sugars so don’t expect the hydrometer to fall below 1.010) then check the temperature of the liquid in the fermenter. It needs to be between 18-22°C. If it is too cold or too warm you will need to put it somewhere to get to the right temperature. This can take 24 hours to acclimatise to the correct temperature. Fermentation may start again within 12 hours, but can take up to 24 hours to show signs on fermentation once its back at the desired temperature.
Making a Yeast Re-Starter
After 24 hours at the right temperature, if there is still no activity and a hydrometer reading shows that there has been no movement, then you have a stuck fermentation.
You will need to introduce more yeast by way of a yeast starter to get the fermentation going again.
The yeast will need to become accustomed to the brew as any alcohol already created can stun or even kill the new yeast. So we need to rehydrate the yeast and introduce the brew to them gently.
Put 2 finger widths of water (20°C) in a pint glass.
Put in 1 level teaspoon of sugar and stir until dissolved. This can be supermarket sugar.
Add 1 teaspoon of yeast nutrient and stir until dissolved.
Sprinkle on the yeast.
Cover the glass with clingfilm and prick a small hole in the top.
Put in a warm place (20°C) for 3-4 hours. A foam should have developed on the top and there should be bubbles forming.
Take a small amount of your brew from your fermenting vessel.
Add 2 fingers width of your brew to the yeast water in the pint glass. Gently stir.
Re-cover and put back into your warm place (20°C) for 2-3 hours. You should notice bubbles and a small foam continuing to form.
Now add 2 more fingers width of your brew to the pint glass.
Re-cover and put back into your warm place (20°C) for another 2-3 hours. You should notice bubbles and a small foam continuing to form.
The yeast will now be ready to get to work.
Pour the contents of the pint glass into your fermenter and stir gently.
Make sure your brew is at a steady temperature between 18-22°C
Cover and leave the yeast to get to work.
Within 24 hours you should notice fermentation activity. If you want to check its progress, use your hydrometer and compare to the previous reading. If it is dropping, you know it is fermenting.
A Final Thought…
It is very rare that you need to pour a brew down the sink (unless it has been infected) so don’t be hasty and judge that your brew is ruined just because you have a funny smell, it tastes a bit sharp, it appears to have done nothing or you forgot to add pectolase.
Just put the lid back on or the airlock in. Then drop us a line with some pictures, a hydrometer reading and a brief history of your brew.
We’ll look at your enquiry and get back to you with some advice and guidance on how to proceed. It’s very rare that a brew can’t be saved!
Hope these little tips help whether you are a novice or a regular brewer.
