Recipe 1,2 and 3: Meads take up CO2

An interesting little observation.

After adding CO2 to the meads yesterday, the airlock was filled with fresh water and attached to the carboys. The water levels in the two chambers were equal.

Within a short time the meads began to generate a small vacuum shifting the levels of the airlock. This must be an uptake of CO2 in the meads. I thought the meads would be saturated by CO2, but apparently not. This will also push pH down a bit.

Recipe 1,2 and 3: Final tasting

This weekend I decided to do the final adjustments to my meads.

Recipe 1: Cyser
This mead has been covered in dark plastic for quite a while now. When I removed the plastic I was surprised to see that it had almost turned black (?) - Not sure that was a good sign. Opening the 20 L volumetric flask, I was a little hesitant to smell it. But to my surprise it just fantastic :o). I took a sample and found that when the light paths was reduced, the mead had a very pleasing dark golden color. A thin layer of precipitate was found on the bottom so now it is even more clear. pH was measured with strips to about 4. So looks good. The taste was the best surprise. The stinging acidic taste was almost gone, and the sweetness of the honey is not overpowering the the acidity. All in all, I have much more hope for this mead now. Since this mead did not ferment to very low sugar and has killed any attempt to be re-started, I am not worried that it will start up again later. Bisulfite/sorbate was therefore NOT added - hope I will not be proven wrong (again) on this.

Recipe 2: Sack mead
The mead is very clear and with only a week yellow color. pH was measured to just above 4, again with strips. It does not have much initial taste but still an acidic aftertaste. Not as pleasant as my cyser but then again I should probably not have tasted this mead after the cyser.

Recipe 3: Elderberry Melomel
This is my experimental mead. It is very strong tasting and has clear red color, which is less intense than for example a red wine. It is quite acidic tasting but pH is up between 4 and 5. I think the alcohol is quite high so it should be well protected against microbial growth despite the high pH. The taste of anise that I added several times was gone - again. Perhaps the anethole (which is responsible for the fragrance of star anise) is not stable in the acidic alcoholic solution? Not sure of the degradation pathway though.

Finally I covered all 3 meads with 5 L CO2 each from the reaction sodium bicarbonate/citric acid as described earlier.

.... and then it was time to clean up..... In the near future I think I will by myself a pH meter .........

Weighing the hive (continued 4) - my results are spot on!

Just found this PDF on from 2007 (DCA Aarhus Universitet). They have measured the weight of their hives in exactly the same way as I have done this winter, so the results can easily be compared. On page 2 you find the weight loss to be very close to the 40 g that I have also observed. Also, they observe that the weight loss is approximately linear, just like I do.
Link to PDF

Weighing the hive (continued 3) - spring is coming, slowly

It is now the middle of February and time for another weighing. Going to the garden you can feel that the spring is coming. The first spring flowers are already here, snowdrops and winter aconite.

Now, back to the bees. The mass of the hive was today 23.4 kg, and plotted into the graph, the use of food is still pretty constant - about 40-41 g/day as indicated by the slope. So it does not look like the bee have collected anything from these first flowers.

In my last entry I estimated that for the winter the bees would need about 10 kg of food to sustain the colony throughout the winter.

But what does an empty hive weigh. I have an extra (identical) box with bottom, so I filled it with 10 plates with wax, and tied it up with the same band as the actual bee hive. That amounts to 6.7 kg.

When exchanging the plates with some from last year which was fully built and  a bit of honey in, it weighed a total of 10.8 kg.

A bee weighs 0.1 g, give and take, so a winter hive containing less than 10000 bees, the bees alone will not even weigh 1 kg.

All in all, with only a little honey and a colony of bees the hive the critical mass of the hive would probably be say 10 kg and the bees would starve. Since the bees in a winter cluster are not very mobile and probably would not find honey at the very ends of the of the hive, the mass should never come below 12 kg

With 10 kg of food for the winter the minimum mass to start the winter with is about 22 kg, so give a bit extra the hive should weigh minimum 25 kg by the end of October.

I started the winter with 31 kg, so I will probably have way to much food left in the hive by March. I am expecting to remove 2-3 full plates so that there will be space for breeding in the early spring. What a waste of Apivert....

Weighing the hive (continued 2)

Once during January and here at the end of the month I measured the mass of my hive again. January has been a cold month (danish standards) and the average temperature was significantly different than for December.

Based on this I expected the use of food to increase during the past 2 weeks of January as a consequence of the the decreased temperature - but this was apparently not the case

As shown in the graph the loss of mass of the hive is pretty much constant from end November till now - no temperature dependence at all for the range -5 C to 5 C.

Considering the errors of the measurement:
- not super accurate suitcase scale used
- wet / dry hive (snow removed)
..then I would say that the use of a linear regression line is pretty valid.

As can be read from the slope the mass loss has in average been 42 g per day. In even numbers that is:
= 300 g/week or
= 1250 g/month
So for 5 months, November,December, January, February and March it totals to 6.25 kg as an absolute minimum. With the initial drop in mass of about 3 kg the hive should have about 10 kg of food available before winter, i.e. more than 4, or lets say 5 full frames of food reserve as an absolute minimum. when using a 12x10 box with 10 frames (warm built) as winter hive.

I am wondering if similar data is available for other hives. This would give an idea of how much variation can be expected. Otherwise I will probably do the same next year to see if I can repeat the results.

Recipe 3: Melomel of elderberries with star anise (continued 4) - pH adjustment and sweetening

My elderberry melomel was now up for some final adjustments

Opening the fermenter the smell is very nice but also acidic. Basic measurements:
pH around 4
denstiy 1.008

The taste was very acidic with a harsh aftertaste. I know the fresh elderberry juice has a very similar taste which is very well complemented by the sweetness of honey. Ergo, I would have to add quite a bit of honey to this mead to get it to taste like I planned for.

Also I figured I could remove some of the acidity by adding K2CO3 like I did previously

The taste of the star anise was gone - so a lesson for the future is not to add taste components until AFTER the fermentation. So I would have to redo this.

When adding honey I did not want the fermentation to start up again, so bisulphite/sorbate also had to be done

So first step was to move the mead to my 10L plastic carboy. Even though it is pitch black when looking into the fermeter, the sample for density has a nice light red appearance. The mead is also crystal clear. When the fermeter was emptied the yeast in the bottom was like a thin pitch black layer - wondering if the yeast take up the color components during the fermentation?

Then it was time to add the honey. From my sack mead I knew that I would get a density of 1.120 from adding 7.2kg of honey in 20L, so to raise the density from 1.008 to 1.025  in 8 L I would need about 400 g of honey. I had a half full glass with 270 g of honey so I figured I would start with this. 200 ml of water was boiled with 0.5g of star whole star anise and poured onto the honey to dissolve this. when dissolved, the solution was added to the carboy.

Shake and wait a few time and the density was now 0.016. The taste was still very acidic and the honey could hardly be tasted. and neither could the star anise.

To knock out the yeast I wanted to add a premixed bag of Bisulfite/Sorbate, but the packages is for a 20 L batch. When the bag is opened it is clear that there are two different types of particles in there. Since the content was so inhomogeneous I decided to make a slurry in 100 ml and then add about 40 ml to the batch.

So far so good and time was up for the day but during the following week I had time to finish up.

Again I decided to add base rather than any acid adjustments. I did the same tasting setup as I did for the sack mead. To 10 ml of mead a stock solution of K2CO3 (0.3g in 4 ml) in steps of 0.1 ml. I ended up adding 0.2 ml for the most pleasant taste but even 0.3 was quite OK. Considering that 0.2 ml corresponds to adding 12 g of K2CO3 to my 8 L batch there must be loads of acids in there. All in all I decided to add 10 g

To get some taste of star anise I crushed 0.80 g (0.1g/L) and boiled it in 50 ml of water for 10 min under lid. I put the crushed star anise in a long tea bag which was lowered into a 50 ml in a metal measuring cup (100 ml) which again was put in a pot with water. Little tedious, but it worked nicely. I did not get a picture of it boiling but here is one of the general set-up.

The 50 ml was then used to dissolve another 140 g  (410 g in total) of honey and, wow, did that smell and taste good :o). Finally I added the 10 g of K2CO3 to get it dissolved and add the entire solution to the carboy......

DUMB ASS IDEA

Since CO3(2-) is very basic the pH star anise/honey solution probably rose to beyond 10. A nasty smell of ammonia suddenly filled my nose and even though the carbonate was not fully dissolved I just added the entire slurry to the carboy to get pH down as fast as possible, closed the carboy and shook it well over and over for about 30 min, remembering to degas the carboy after each shake.

Fortunately no harm seemed to have been done.
pH about 4.5 (must be very buffered to take that much CO3(2-))
density 1.025 (spot on)
Taste - wow, so nice and with just a hint of anise in the aftertaste together with a little bite of the acid.

Since the solution was so strongly colored, reading pH was not so easy - perhaps pH was closer to 4? 

Considering that this was just a test for fun I think this is going to be my best mead so far, but lets see what maturing does for the taste

Next step is bottling in a few months from now.

Recipe 2: Sack mead (continued 5) - adjusting pH

Long time since since I did anything to my meads, but last weekend it was time to try to adjusting the taste by acid addition.

Opening the fermenter with sack mead I am still surprised about how pleasant the smell is. The last yeast has precipitated on the bottom and it is now totally clear.

The basic measurements:

pH: about 3.5

density: 1.015

I was hoping that the pH had raised a bit due to degassing of CO2 but I cannot see any difference from my last measurements. The density is still 1.015, so there is absolutely no indications of even slow fermentation - great :o)

The mead was then racked to it final "resting place", a plastic carboy for maturing, and to get rid of the last precitipate. And then it was time for tasting, but...........

Tasting the mead was not so pleasant. The acid taste is very stringent and overwhelming for my taste. My initial idea was to adjust acids by adding citric acid, malic acid, or tartaric acid (or a blend of these), but I skipped the plan and decided to add base instead to raise pH.

For this purpose I used K2CO3. The carbonate is already an intricate part of the mead and potassium is without taste and has no limits in terms of food safety.

Only question was how much acid to add. To be a little systematic I prepared a stock solution of K2CO3 (0.30g of K2CO3 to 4 ml of water using a 10 ml disposable syringe)

Then I just took a few samples of mead (10 ml again with a 10 ml disposable syringe) repeated added 0,10 ml of stock solution (using a 2 ml disposable syringe) until the taste was just right. To make sure that I did not suddenly get a taste of something very basic I measured the adjusted mead with pH strips before tasting.

After adding 0.1 ml the acid taste was reduced significantly but still there, and the mead had a very different and much more appealing mouth feel, so I did not feel that I had to add any more. pH was now about 4.5 measured with strips. 

Since my batch is now reduced to about 17 L this means that I would have to add 170 ml to get the same effect. With a concentration of 0.3/0,004=75g/l that corresponds to adding 12.75g of K2CO3. To be a bit on the "safe side" I decided to add 10g dissolved in 100 ml of water. Capping the carboy and giving it a good shake followed by about 30 min rest. A final check of pH was about 4.5 - as expected :o)

Finally, the airlock was attached and the carboy put aside. I did not add CO2 since a lot of CO2 was released when the carboy was shaken. I guess that this would be enough to cover the surface. 

Next step is bottling so now I will have to see where I can get some adequate bottles for this.