Weighing your BOMM

[renrutle]

After a bit of a delay I got 3 batches started this last Saturday (3-16) and have some data to report.
I am taking both a weight and a SG reading. I hope to have some graphs soon and will post a link to the google doc once it is ready. All three have ~2.3# of honey and started at an OG of a bit over 1090. All weights below are in grams.

So far the ratio of Δ weight to Δ SG is running between 4.6 and 3.3 with an overall average of 3.7.


BOMM 1

Wt Honey 1074
Wt Total 5305
Day # - Wt g - SG
Day 1 - 5305 - 1094
Day 2 - 5299 - 1092
Day 3 - 5275 - 1086
Day 4 - 5250 - 1079
Day 5 - 5225 - 1072
Day 6
Day 7


BOMM 2

Wt Honey 1102
Wt Total 5400
Day # - Wt g - SG
Day 1 - 5400 - 1092
Day 2 - 5399 - 1090
Day 3 - 5376 - 1085
Day 4 - 5352 - 1079
Day 5 - 5328 - 1073
Day 6
Day 7


BOMM 3

Wt Honey 1080
Wt Total 5384
Day # - Wt g - SG
Day 1 - 5384 - 1092
Day 2 - 5376 - 1089
Day 3 - 5554 - 1084
Day 4 - 5330 - 1078
Day 5 - 5307 - 1071
Day 6
Day 7

Edit:
All additional notes will be published here.
https://docs.google.com/spreadsheets/d/1HO9oETsDfIBzg3mDongO-Axkk5r4g5PK7ZwKrVTFe90/edit?usp=sharing

 

[renrutle]

Today I started a new traditional mead using 71B in a 1 gallon jar. I have instrumented it with a TILT wireless hydrometer so that we can finally compare SG readings to weight lost and see how good our calculations have been. I weighed the honey that went into it to the nearest gram, and I weighed the entire jar, TILT included, to get a starting weight measurement. OG, as reported by TILT, is right on the money at 1.105 SG. I have two rounds of nutrient additions at the first and second sugar break that have yet to be done, so I'll measure the impact of those on weight also. I'll keep track of the weight measurements when I perform them and time and date stamp them so that they can later be compared with the TILT's SG measurements at the same time. At some point I'll post the data so that everyone can make their own comparisons if they want to and draw their own conclusions about how accurate (or not) this weighing method actually is.



@renrutle: where is Magnolia located? When I click on your locator, it gives a BestBuy store in Austin, Texas.

Thanks for running your trials. I'm using the turkey baster method to fill the hydrometer tube for taking measurements.

Magnolia is about 50 NW of Houston on 249. The link works for me.

 

[NeverDie]

After a bit of a delay I got 3 batches started this last Saturday (3-16) and have some data to report.
I am taking both a weight and a SG reading. I hope to have some graphs soon and will post a link to the google doc once it is ready. All three have ~2.3# of honey and started at an OG of a bit over 1090. All weights below are in grams.

So far the ratio of Δ weight to Δ SG is running between 4.6 and 3.3 with an overall average of 3.7.


BOMM 1

Wt Honey 1074
Wt Total 5305
Day # - Wt g - SG
Day 1 - 5305 - 1094
Day 2 - 5299 - 1092
Day 3 - 5275 - 1086
Day 4 - 5250 - 1079
Day 5 - 5225 - 1072
Day 6
Day 7


BOMM 2

Wt Honey 1102
Wt Total 5400
Day # - Wt g - SG
Day 1 - 5400 - 1092
Day 2 - 5399 - 1090
Day 3 - 5376 - 1085
Day 4 - 5352 - 1079
Day 5 - 5328 - 1073
Day 6
Day 7


BOMM 3

Wt Honey 1080
Wt Total 5384
Day # - Wt g - SG
Day 1 - 5384 - 1092
Day 2 - 5376 - 1089
Day 3 - 5554 - 1084
Day 4 - 5330 - 1078
Day 5 - 5307 - 1071
Day 6
Day 7

Are they each one gallon in fluid volume? Which yeast? What temperature? Which nutrient protocol? What water did you use?

I'm guessing you're using 1388 as the yeast, given that it's BOMM, but it doesn't hurt to be sure.

Thanks for posting your data, and I'm looking forward to your graphs!

 

[NeverDie]

I recently started 71B and Fresco trials, with starting OG's either at or near 1.105, and each monitored with a TILT. For 71B, you can view the real-time progress here:https://docs.google.com/spreadsheets/d/1WGbJzJ4C78lqVa2D678XE5Rov4gVgeAeJFAfthuz-Pw/edit?usp=sharing

and for Fresco here:https://docs.google.com/spreadsheets/d/1UameIZ6ks_67gMgiSO9XC1P1eYEtDXUQTnHbteS1s2o/edit?usp=sharing

Here's my dataset in CSV format:
Honey(g),Net(g),SG
1049,3524,1.105
1049,3475,1.085
1049,3448,1.078
1049,3424,1.071
1049,3416,1.068
1049,3414,1.067
1049,3411,1.067
1049,3403,1.065
1049,3394,1.062
1049,3379,1.058
1049,3357,1.054
1049,3341,1.048
1049,3313,1.041
1049,3286,1.031
1042,3503,1.103
1042,3488,1.097
1042,3463,1.09
1042,3452,1.087
1042,3450,1.086
1042,3438,1.082
1042,3426,1.078
1042,3404,1.071
1042,3368,1.061
1042,3343,1.053
1042,3303,1.04
1042,3265,1.027

With the data now collected, the next step will be to do a regression analysis to come up with a predictive equation. i.e. given the weight of the honey used initially and given the weight of the water+honey solution, predict the SG that would correspond to that. I may have to represent the data differently than that, but I'll see if that works.

I plan to use either Excel or Libra Calc to crunch the numbers.

 

[renrutle]

Are they each one gallon in fluid volume? Which yeast? What temperature? Which nutrient protocol? What water did you use?

I'm guessing you're using 1388 as the yeast, given that it's BOMM, but it doesn't hurt to be sure.

Thanks for posting your data, and I'm looking forward to your graphs!

They are all in gallon glass carboys with orange blossom honey. Using WLP570 though in these three batches. Once my batch with 1388 finishes in a week or so I will re-pitch that in two or three more 1 gallon batches. Counter temp is running steady at 68F. I'm following the 1/3, 2/3 schedule on the calculated SG readings for nutrient additions. I'm on a well so it is all well water; about 50% through the RO filter and the rest straight from the tap.

 

[renrutle]

I recently started 71B and Fresco trials, with starting OG's either at or near 1.105, and each monitored with a TILT. For 71B, you can view the real-time progress here:https://docs.google.com/spreadsheets/d/1WGbJzJ4C78lqVa2D678XE5Rov4gVgeAeJFAfthuz-Pw/edit?usp=sharing

and for Fresco here:https://docs.google.com/spreadsheets/d/1UameIZ6ks_67gMgiSO9XC1P1eYEtDXUQTnHbteS1s2o/edit?usp=sharing

With the data now collected, the next step will be to do a regression analysis to come up with a predictive equation. i.e. given the weight of the honey used initially and given the weight of the water+honey solution, predict the SG that would correspond to that. I may have to represent the data differently than that, but I'll see if that works.

I plan to use either Excel or Libra Calc to crunch the numbers.

I hope you don't mind but I added your data to my spreadsheet. Ignore the stuff below the charts on the first tab. those are random notes and calculation to try and make sense of the data.

https://docs.google.com/spreadsheets/d/1HO9oETsDfIBzg3mDongO-Axkk5r4g5PK7ZwKrVTFe90/edit?usp=sharing


Mine are about a week behind yours. I am also planning to run a batch with orange blossom and RedStar Premier Blanc yeast and a parallel one with just sucrose at the same OG. I'm thinking that sucrose should give a baseline and the Premier Blanc should have no problem consuming all the sugar to arrive at a total weight loss.

When did you make your nutrient additions?

I'm thinking that this may be as simple as multiplying the honey weight by some factor (possibly involving on the starting gravity) to arrive at the weight loss that corresponds to the 1/3 and 2/3 SG readings. Wishful thinking at this point in the data collection process.

 

[NeverDie]

I hope you don't mind but I added your data to my spreadsheet. Ignore the stuff below the charts on the first tab. those are random notes and calculation to try and make sense of the data.

https://docs.google.com/spreadsheets/d/1HO9oETsDfIBzg3mDongO-Axkk5r4g5PK7ZwKrVTFe90/edit?usp=sharing


Mine are about a week behind yours. I am also planning to run a batch with orange blossom and RedStar Premier Blanc yeast and a parallel one with just sucrose at the same OG. I'm thinking that sucrose should give a baseline and the Premier Blanc should have no problem consuming all the sugar to arrive at a total weight loss.

When did you make your nutrient additions?

I'm thinking that this may be as simple as multiplying the honey weight by some factor (possibly involving on the starting gravity) to arrive at the weight loss that corresponds to the 1/3 and 2/3 SG readings. Wishful thinking at this point in the data collection process.

I don't mind at all. That's why I posted the dataset: so that anyone can use it however they want.

I used the 6b protocol for BOMM that's on Bray's website: https://denardbrewing.com/blog/post/brays-one-month-mead/
So, to answer your question, I do the nutrient additions 1/3 up-front, 1/3 at the first sugar break, and then 1/3 at the second sugar break. On this first pass I didn't account for the extra weight of the nutrient additions at the first and second sugar breaks, but it's probably not significant anyway.

Therefore, there are really only two SG's that I need to predict based on the amount of weight lost: the first sugar break and the second sugar break. Like you, I've hopeful that the math will be a simple linear relationship in that area of interest.

I don't really need to know the SG for when fermentation halts. All I need to know is when the weight stops changing, because I'm assuming that is the indicator for when fermentation is finished.

 

[renrutle]

I didn't account for the extra weight of the nutrient additions at the first and second sugar breaks, but it's probably not significant anyway.

I guess I'm using his 6a protocol. I haven't bought any Fermaid O. 1/4 tsp DAP and 1/2 tsp Fermaid K weigh in at 4-5 grams. 0.4 tsp of Fermaid O is probably 3-4 grams. I do add nutrients and 1/4 tsp potassium bicarbonate at the start.

 

[NeverDie]

I ordered one of these to perhaps do some continuous logging of weight changes:
https://www.amazon.com/gp/product/B01MFHGU6I/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1
That would make collecting a lot of datapoints much easier in the future, since it would be fully automatic.

 

[Blacksmith1]

Pretty cool little toy.

 

[NeverDie]

I plotted the SG vs weight lost for the first part of my dataset, which is for yeast 71B that had OG 1.105:

It's almost linear, but not quite.

Given the OG at 1.105, the first sugar break would be at 1.070 SG, and the second at 1.035 SG.

Although I didn't capture weight measurements at exactly those SG points, interpolating the data suggests that the weight lost corresponding to 1.070 SG was 103g, and the weight lost corresponding to 1.035 SG was 223g. i.e. The weight lost at the second sugar break was more than twice the amount lost at the first sugar break. I'm not sure what accounts for that.

When I find time I'll run the numbers for the Fresco yeast, which was the other half of the dataset, and which had an OG of 1.103, and see how that compares.

I think in the future that continuously capturing the weight data using the arduino scale, which could time and date stamp all the entries, will prove useful, because then I'd have the exact weight lost that corresponds to the exact SG as measured by the TILT. i.e. no interpolation error, but the spot on weight lost for any SG of interest.

 

[NeverDie]

Here's the graph for the Fresco yeast dataset:

It's the same sort of thing: there's a slight bend that happens in the middle that keeps it from being a straight line. So it too will have more than double the weight lost by the second sugar break as by the first sugar break.

 

[NeverDie]

Anyhow, until the anomaly is explained, a simple formula that appears to match the data fairly closely for the first sugar break is just:

First sugar break: (grams of honey)/10

To be conservative, just double that number to get the grams of weight loss for the second sugar break. i.e.

Second sugar break: (grams of honey)/5

Of course, one can crank out more precise numbers, but these are easy to remember and work with.

 

[Maylar]

Is the x axis the weight?

And I need to point out that temperature will have a direct impact on the rate of change.
I'm also surprised that it seems to be such a linear function. I would have expected some 2nd order behavior as the ferment nears completion.

 

[NeverDie]

Is the x axis the weight?

And I need to point out that temperature will have a direct impact on the rate of change.
I'm also surprised that it seems to be such a linear function. I would have expected some 2nd order behavior as the ferment nears completion.

X-axis is amount of weight lost, as compared to the starting weight, measured in grams. Verticle axis is the SG, as measured by the TILT. There's no time component here, so no rate of change can be inferred from this plot. You can, however, see the rate of change from the TILT plot on the link I have provided.

Actually, I was expecting that it would be perfectly linear, except maybe a little off toward the beginning as the solution becomes saturated with CO2 that doesn't get immediately released. The OP calculated that might be as much as 7g per gallon. I may try measuring that experimentally when I get my vacuum chamber hooked up. Aside from that, I'm honestly surprised that the plot appears to have a slight bend in the middle (which is what I'm referring to as "the anomaly") rather than being a straight line through all the points past the beginning (since temperature is pretty stable, as can be seen in the TILT plot).

Looks as though with both yeasts the bend happens around the same place, right around 1.05-1.07SG. Maybe some kind of change in metabolism happens at that point that's not purely just the sugar metabolism into CO2 and alcohol that we've been modelling? I mean maybe it's around that point where the yeast switches from digesting glucose into digesting more complex sugars like sucrose/fructose, and that somehow affects the SG a little differently? I have no clue, but that's my wild guess. I have read, though, that yeast is preferential that way in the order in which it digests sugars (least complex first and more complex last).

 

[NeverDie]

Well, interestingly, looking at the TILT curve (which anyone reading this can also do by clicking on the links I had provided above), with both yeasts there's a curve inflection in the same 1.05-1.07SG range. So, I do think something physical is going on there, and it's not just some artifact of the data gathering.

 

[NeverDie]

I hope you don't mind but I added your data to my spreadsheet. Ignore the stuff below the charts on the first tab. those are random notes and calculation to try and make sense of the data.

https://docs.google.com/spreadsheets/d/1HO9oETsDfIBzg3mDongO-Axkk5r4g5PK7ZwKrVTFe90/edit?usp=sharing


Mine are about a week behind yours. I am also planning to run a batch with orange blossom and RedStar Premier Blanc yeast and a parallel one with just sucrose at the same OG. I'm thinking that sucrose should give a baseline and the Premier Blanc should have no problem consuming all the sugar to arrive at a total weight loss.

When did you make your nutrient additions?

I'm thinking that this may be as simple as multiplying the honey weight by some factor (possibly involving on the starting gravity) to arrive at the weight loss that corresponds to the 1/3 and 2/3 SG readings. Wishful thinking at this point in the data collection process.

Looking forward to seeing how your data evolves and whether it exhibits a similar "shift" part way through the fermentation. I previously thought you had started on February 20 (as shown in your OP post), but I guess you were measuring only weight and not SG back then.

Looks as though the [total honey weight/10] rule fits pretty well for the first sugar break on one of your ferments and is a little premature on the other. I figure, though, to be conservative it's better to error on the side of adding a little too early than too late. That said, I hope you find a better formula than me.

 

[renrutle]

Looks as though the [total honey weight/10] rule fits pretty well for the first sugar break on one of your ferments and is a little premature on the other. I figure, though, to be conservative it's better to error on the side of adding a little too early than too late. That said, I hope you find a better formula than me.

Anyhow, until the anomaly is explained, a simple formula that appears to match the data fairly closely for the first sugar break is just:

First sugar break: (grams of honey)/10

To be conservative, just double that number to get the grams of weight loss for the second sugar break. i.e.

Second sugar break: (grams of honey)/5

Of course, one can crank out more precise numbers, but these are easy to remember and work with.

My data seems to be tracking closely with yours.
First break is at:
Δ weight/ Honey Weight = ~10%

I have another day or so to reach the second break but it looks like it will be close to the ~20% weight loss you noted.

To be clear, this weight loss is 10% and 20% of the weight of the honey not the total weight of the fermenter.

 

[renrutle]

The batch with orange blossom and Premier Blanc hit the first break today also at the ~10% loss mark.

First sugar break: (grams of honey)/10

 

[NeverDie]

Yesterday I started a smaller batch at OG 1.103 using just 860g honey and QA23 yeast. When there's enough data I'll post it. That way we'll see if the same formula scales to a smaller batch or whether it's particular to the 1 gallon batch size we've both been teting so far. I expect it will still hold true, but we shall see.

 

[renrutle]

Yesterday I started a smaller batch at OG 1.103 using just 860g honey and QA23 yeast. When there's enough data I'll post it. That way we'll see if the same formula scales to a smaller batch or whether it's particular to the 1 gallon batch size we've both been teting so far. I expect it will still hold true, but we shall see.

I had a similar thought but was going to go bigger. I think I have a 3 gallon vessel I can repurpose. Need to verify my scale can handle the additional weight. I know the scale can handle 2 gallons. What was your final volume?

I started with this scale which tops out at 6 kilos.
https://www.amazon.com/gp/product/B01JK4XPVW/ref=oh_aui_search_asin_title?ie=UTF8&psc=1

I have been using this one for most of the trials. It tops out at 10 kilos.
https://www.amazon.com/gp/product/B07G2YTDQM/ref=oh_aui_search_asin_title?ie=UTF8&psc=1

 

[NeverDie]

I had a similar thought but was going to go bigger. I think I have a 3 gallon vessel I can repurpose. Need to verify my scale can handle the additional weight. I know the scale can handle 2 gallons.

I started with this scale which tops out at 6 kilos.
https://www.amazon.com/gp/product/B01JK4XPVW/ref=oh_aui_search_asin_title?ie=UTF8&psc=1

I have been using this one for most of the trials. It tops out at 10 kilos.
https://www.amazon.com/gp/product/B07G2YTDQM/ref=oh_aui_search_asin_title?ie=UTF8&psc=1

3 gallons of water would be 25 pounds, not counting the weight of the container. Higher density liquid is going to weigh more. You'd either need a scale that can handle more weight or else multiple scales like the one you already have and then add up the weights across them.

 

[renrutle]

After a lot of data collection and a bit of number crunching I submit the following for consideration.
The correlation between weight loss and SG loss looks quite good for the BOMM data sets. I included data for a water-sucrose ferment. (The lower purple line.) I expected this to have a different slope since sucrose is 100% fermentable by weight. While the sugar in honey is 100% fermentable it is only 80%-90% sugar and therefore 80%-90% fermentable by weight.

BOMM 1-3 are Orange Blossom and White Labs WLP570
BOMM 6 is Orange Blossom and RedStar Premier Blanc
BOMM 4 and 5 data was provided by NeverDie and are with Lalvin 71B-1122 and Fresco if my notes are correct.
Sucrose is with table sugar and RedStar Premier Blanc
These are all 1 gallon batches with an OG between 1.092 and 1.112.

I believe that NeverDie is running a smaller than 1 gallon batch and I plan to do a 2-2.5 gallon batch once I harvest the 1388 from a batch not covered by this experiment.

From what the data currently shows I am comfortable stating the following:
If using honey in a 1 gallon batch you can approximate the 2/3 and 1/3 sugar break nutrients additions at the 10% and 21% weight loss points.

 

[NeverDie]

After a lot of data collection and a bit of number crunching I submit the following for consideration.
The correlation between weight loss and SG loss looks quite good for the BOMM data sets. I included data for a water-sucrose ferment. (The lower purple line.) I expected this to have a different slope since sucrose is 100% fermentable by weight. While the sugar in honey is 100% fermentable it is only 80%-90% sugar and therefore 80%-90% fermentable by weight.

BOMM 1-3 are Orange Blossom and White Labs WLP570
BOMM 6 is Orange Blossom and RedStar Premier Blanc
BOMM 4 and 5 data was provided by NeverDie and are with Lalvin 71B-1122 and Fresco if my notes are correct.
Sucrose is with table sugar and RedStar Premier Blanc
These are all 1 gallon batches with an OG between 1.092 and 1.112.

I believe that NeverDie is running a smaller than 1 gallon batch and I plan to do a 2-2.5 gallon batch once I harvest the 1388 from a batch not covered by this experiment.

From what the data currently shows I am comfortable stating the following:
If using honey in a 1 gallon batch you can approximate the 2/3 and 1/3 sugar break nutrients additions at the 10% and 21% weight loss points.

View attachment 619683

Nice work!

Yes, I am running a smaller batch of somewhere around 2.5-02.8L using 860g of honey and QA23 as the yeast. OG was 1.103, so the first sugar break should be 1.069. As it turns out, it just now reached that first sugar break, and 102g of weight were lost, so more than the predicted 10% if it had been a 1 gallon batch. I'll continue tracking it through the second sugar break and then post all the measurements that I took relating to this batch.

I wonder if the difference can be attributed in some way to the QA23 yeast? I think I've read that some yeasts are able to digest more than others. For instance, allegedly 71B can digest malic acid. Not sure about QA23.

I'll be very interested to hear how the numbers for your larger batch come out.

The more datapoints the better. If anyone else reading this would like to contribute data, it would be very helpful and much appreciated!

 

[NeverDie]

I was surprised to read that some people don't actually mix their honey, but instead let it sit at the bottom:

Allegedly (I haven't tried it) the yeast will eat through it anyway. I would think that it would be a slower process than if it were all mixed together, but who knows?

I suppose if you had a very straight sided transparent container (not rounded, as in the photo), you could draw lines at the 1/3 and 2/3 mark on the honey height and maybe use that are your sugar break indicator? I'm sure it wouldn't be as precise as weighing, but then again, maybe close enough? And it would be even quicker to check than weighing, and obviously much quicker than taking a formal manual hydrometer reading.

Come to think of it, any container would do. Just add 1/3 the honey first. Mark the height of that. Then add another 1/3 of the honey and mark the height of that. Add the final 1/3, then add the rest of the must on top without stirring.

Hmm.. I''m intrigued!

 

[NeverDie]

I've taken to weighing to decide when fermentation is done. It's actually more sensitive than SG, because a drop of just one point in SG translates to multiple grams of loss. So, if you measure to the nearest gram, and nothing changes over enough time, then it's done. At least that's the theory I'm going with for now.

 

[Miraculix]

I've taken to weighing to decide when fermentation is done. It's actually more sensitive than SG, because a drop of just one point in SG translates to multiple grams of loss. So, if you measure to the nearest gram, and nothing changes over enough time, then it's done. At least that's the theory I'm going with for now.

Makes sense! Actually a very good thing as you don't even need to open the fermenter.

 

[NeverDie]

Makes sense! Actually a very good thing as you don't even need to open the fermenter.

Right! That's the whole idea in a nutshell. Plus it's faster, objective (you have a digital number on the scale and are not squinting at a hydrometer and trying to decide what the nearest SG is), and no contamination risk.

According to this criteria, one of the yeast strains in my experiment may have finished. All the rest have dropped by at least 1 gram since the last measurement on 3/27. Some of that may just be off-gassing of dissolved CO2, but this is a conservative approach. I'll give it more time and measure again.

 

[NeverDie]

My QA23 batch reached its second sugar break at 1.034. Total weight lost was 191g. That's 22% of the 860g of honey that was added at the beginning.

So, not spot on with the earlier 1 gallon predictions that renrutle summarized above, but not terribly far off either.


So, if you assume 11% honey weight lost for the first sugar break, and 22% honey weight lost for the second sugar break, you get an accurate prediction at this smaller scale. That compares to 10% and 21% at the 1 gallon scale.

 

[renrutle]

My QA23 batch reached its second sugar break at 1.034. Total weight lost was 191g. That's 22% of the 860g of honey that was added at the beginning.

So, not spot on with the earlier 1 gallon predictions that renrutle summarized above, but not terribly far off either.


So, if you assume 11% honey weight lost for the first sugar break, and 22% honey weight lost for the second sugar break, you get an accurate prediction at this smaller scale. That compares to 10% and 21% at the 1 gallon scale.

That data looks promising to support this method of approximating Bray's official procedure.

Can you keep track of these 6 data points for each of the batches you are making? I am doing the same. My chemistry-math research indicates that the weight change plotted vs the SG change should be linear. Our experimental data seems to back this up.

Honey weight
Volume
Beginning weight
Final weight
Starting SG
Final SG

I've taken to weighing to decide when fermentation is done. It's actually more sensitive than SG, because a drop of just one point in SG translates to multiple grams of loss. So, if you measure to the nearest gram, and nothing changes over enough time, then it's done. At least that's the theory I'm going with for now.

I am waiting on my 1388 batch to stop losing weight to begin a ~2 gallon batch. Current weight loss is ~2-3g/day.

 

[NeverDie]

That data looks promising to support this method of approximating Bray's official procedure.

Can you keep track of these 6 data points for each of the batches you are making? I am doing the same. My chemistry-math research indicates that the weight change plotted vs the SG change should be linear. Our experimental data seems to back this up.

Honey weight
Volume
Beginning weight
Final weight
Starting SG
Final SG

It will be some time before I start any new batches. I have something like 30 different batches all in various stages of fermentation right now, and I need to see how they turn out before I start any more. Part of them were experimental batches, and the rest was priming the pipeline so I can have more optimally aged mead in the future.

 

[NeverDie]

The early results are that if I rack the mead off the lees and then give it a thorough degassing in a vacuum chamber, the weight stops dropping.

 

[NeverDie]

The evidence is in, and the weighing method works for determining when fermentation is fully done. By fully done, I mean including degassing/outgassing, because I guess technically speaking fermentation may be done before full degassing/outgassing is complete. As I posted in a different thread, D47 hasn't dropped even 1 gram in the last 6 days, and it is also fully outgassed (if I seal the container the D47 mead is in and shake it up violently, there is no PFFT! when I open it up). It is also fully floculatted and clear. From pitching the yeast to fully finished took about 30 days, plus an additional 6 days to confirm completion using the weighing method.

For automated monitoring of when fermentation is complete using an arduino scale, I'm pretty sure this will work, provided there is no significant scale measurement drift or creep that would throw it off by having the mead constantly sitting on the scale. It seems not to be a problem if using a manual scale where the mead is removed after weighing. So, setting up such an automatically monitored scale will be next to try, with a stable temperature environment.