View Full Version : Fermentation not halted?

05-23-2017, 06:58 AM
Hi all, first time mead here, been brewing beer for almost 15 years. I'm doing a small one gallon batch of mead to see how I like it. It's been sitting around since Jan., looks nice and clear, 13.2% so I thought I'd bottle it. Transferred it from a small demijon to a jug and added potassium sorbate and potassium metabisulphite so I could back sweeten it just a little. Let it sit over night before I added more honey and I have a full rise of my airlock and some tiny bubbles. Shouldn't the two chemicals have killed everything off? Looking for some guidance/opinions on what to do next since I thought there would be no more activity. Added 1/2 tsp of potassium sorbate and just a pinch of the metabisulphite (directions said 1/4 tsp for six gallons, im only doing one gallon.)

05-23-2017, 07:41 AM
Welcome to the forums, Mattheus

So yeah the chemicalls take care of the yeast, but you need more potassium metabisulphite. The ammount you need is probably around 0.5-1 gram, but it depends on highly on pH. The ammount needed to preserve the mead and to kill the yeast are different. The first is for dry meads, the second for backsweetening since commercial yeasts are made so that they can survive low levels of sulphites intended to kill wild yeast and bacteria. Also pH is highly related to the effectivity of the K-meta, so measuring it is usually a good thing, because if not you can add too much or too little.
Here is some info about how sulphites work


to achieve a desired ppm, remember that only 57% of the K-meta is sulphite (so if you add 1 gram, you'll have 570 mg of sulphites/3.8 liters 150ppm, which is enough or too much depening on pH.)
Also its ideal to have little or no yeast left when suing the chemicals, so racking once or twice is recommended.

05-24-2017, 08:19 AM
I'll check that out. I was just following the instructions on the chemicals, but I didn't know about the ph.

05-24-2017, 05:30 PM
I'll check that out. I was just following the instructions on the chemicals, but I didn't know about the ph.

In addition to the K-meta being more effective at a lower pH, there is another reason to watch the pH: taste.

Generally more acid (up to a point of course) adds more mouthfeel. However the exact number can vary depending on the amount of alcohol and residual sugar. That said I generally recommend a range for flavor between pH 3.0-4.0 (usually 3.2-3.8 ). The exact number depends on those other aspects.

There are three core aspects (but I like to include the 4th even if it is only used in very small amounts) to affect flavor and mouthfeel:
1) ABV
2) residual sweetness
3) acidity
(4) Tannins- either directly from the fruit or fruit seed or from oak ageing)

Too much of any of the above is bad. However too little of the first 3 can also be bad. You can make a great mead without using the 4th at all but adding the 4th makes the mead more complex overall and therefore potentially improving flavor.

I know this is not what you asked but it gives you an additional reason to monitor the acidity level