WineXpert Grape skins/ABV (squeezing to get what you want)

[Elmer]

On Saturday I started another batch of WE Selection Brunello.
I followed the directions, even thought I have them mostly memorized.

I dropped the slimy grapeskins in the mesh bag and dropped it in the must. I gave a good stir and took the SG reading 1.085.

So I let it sit for an hour, then I took the bag out and squeezed the heck out of it (which I wish I had planned ahead, since I had all my towels in my pocket and nothing accessible with my newly slimey hands).

Took another SG and was only at 1.090.
I then poured in the yeast and moved on with my day.

However I am under the suspicion that the grape skin bag has alot more slime and sugar that it will impart over the next few days. I can give an SG reading but since fermentation has begun I will not get an accurate reading.

How do I go about getting a decent reading, or do I just assume that it will be more than 11% or 12%
?

How does anyone else handle this?

 

[Boatboy24]

My process on kits with skins is to mix them up and take a reading. Most seem to come in around 1.085-1.090. I stir VERY well prior to this, and mash the bag gently on the bottom/sides of the bucket. I go away for a while (leaving the lid on the bucket), come back, and stir/smash again. I will often do this one more time before pitching the yeast. Total time elapsed being anywhere from 2-6 hours. I take another measure before pitching the yeast and will measure 2-4 times again during the first 24-36 hours. The highest reading I get is the one I use for my starting point.

I started an Eclipse Stags Leap Merlot a few weeks ago. First reading was 1.088, but my highest reading was 1.102.

 

[Elmer]

My process on kits with skins is to mix them up and take a reading. Most seem to come in around 1.085-1.090. I stir VERY well prior to this, and mash the bag gently on the bottom/sides of the bucket. I go away for a while (leaving the lid on the bucket), come back, and stir/smash again. I will often do this one more time before pitching the yeast. Total time elapsed being anywhere from 2-6 hours. I take another measure before pitching the yeast and will measure 2-4 times again during the first 24-36 hours. The highest reading I get is the one I use for my starting point.

I started an Eclipse Stags Leap Merlot a few weeks ago. First reading was 1.088, but my highest reading was 1.102.

I had wanted to do the same, but was running out of time. I wanted to get the yeast in there that night.

That being said, I know the SG was atleast 1.090 and it may have gone higher.
However I am finding that few ever ask me for the ABV% and I know most my wines are usually above 11%,
but I am a stickler for records...

 

[sour_grapes]

Well, 1.090 is already above 12% (assuming you get a final SG of about 0.996 or lower).

I, of course, have the same problem you do in determining starting SG with a grape pack. Like you, I never delay pitching yeast, but once I used BM45 yeast. This is a slow starter, and it allowed the SG to climb to 1.105 before falling due to fermentation. I'd have to check my notes to see exactly where it was upon pitching yeast, but I think it was in the 1.090 ballpark. (This was for a CC Rosso Fortissimo, in case it matters to you.)

 

[DoctorCAD]

Theres more than just sugars in grape packs. Some of the SG comes from the grape solids, so a "true" ABV is probably just a guess.

 

[Elmer]

Theres more than just sugars in grape packs. Some of the SG comes from the grape solids, so a "true" ABV is probably just a guess.

Actually I find that I no longer put the ABV% on my labels.
Realistically the ABV is between 11 and 13.5%, and I dont know that people avoid drinking my wine or any wine for that matter because it is 1% more Alcohol than they expected.

 

[DoctorCAD]

Actually I find that I no longer put the ABV% on my labels.
Realistically the ABV is between 11 and 13.5%, and I dont know that people avoid drinking my wine or any wine for that matter because it is 1% more Alcohol than they expected.

The only time I put ABV is if I plan to compete. I've taken to writing on the bottles with a " Wine Glass Writer " Its a marker that becomes very durable, but can be scrubbed off with soap and water. I put thetype of the wine and its born on date. Thats all...

NO MORE LABLE REMOVALS FOR ME!!!!!

 

[wineh]

Theres more than just sugars in grape packs. Some of the SG comes from the grape solids, so a "true" ABV is probably just a guess.

I can only sort of agree with that. While the grape solids and skins add to the varietal character of the wine, only sugars increase specific gravity or brix.
I recently put on an Eclipse Stag's Leap Merlot, and the SG went from 1.084 to 1.098 by applying several gentle (sanitized hands) squeezing over a couple of hours. A similar tactic with a Brunello style got the SG from 1.082 to 1.094. I now squeeze the grapeskins as part of my procedure for all my kits that have skins.

 

[sour_grapes]

I can only sort of agree with that. While the grape solids and skins add to the varietal character of the wine, only sugars increase specific gravity or brix.

I don't believe that is the case. (At least for specific gravity. Brix, by definition, only includes the sugar.)

If you add non-soluble matter to water, three things can happen: it can float, it can sink, or it can remain in suspension. Matter that sinks or floats does not change the SG of the solution. But if the matter is in suspension, it will affect the SG. (It will make the SG higher if the matter is denser than water, and lower if it is less dense than water.)

 

[DoctorCAD]

Yep, shoe dirt will increase SG, but not brix. Thats why it is impossible to get a true ABV. Anything other than sugar affects SG. We just don't worry about it.

 

[wineh]

I don't believe that is the case. (At least for specific gravity. Brix, by definition, only includes the sugar.)

According to Wikipeadia, even Brix is affected by dissolved matter in suspension, and therefore is only an approximation of sugar content.

If you add non-soluble matter to water, three things can happen: it can float, it can sink, or it can remain in suspension. Matter that sinks or floats does not change the SG of the solution. But if the matter is in suspension, it will affect the SG. (It will make the SG higher if the matter is denser than water, and lower if it is less dense than water.)

Nice description; I think I understand what your saying. So, when kit the instructions call for me to stir in the bentonite before taking my initial SG reading, they want to increase the initial SG, making me think there is more sugar than there really is? Or would the bentonite (or the tiny bit of solids I could squeeze out of a grape pack) even make a measurable (visible on my SG meter) difference?

 

[JDC]

According to Wikipeadia, even Brix is affected by dissolved matter in suspension, and therefore is only an approximation of sugar content.

Nice description; I think I understand what your saying. So, when kit the instructions call for me to stir in the bentonite before taking my initial SG reading, they want to increase the initial SG, making me think there is more sugar than there really is? Or would the bentonite (or the tiny bit of solids I could squeeze out of a grape pack) even make a measurable (visible on my SG meter) difference?

Yes, bentonite will change the SG of your must, just try something next kit you make that has bentonite - measure the SG of your water before you add the clay, mix it well and then measure again (quickly, as it will settle quickly) and you should see a small increase in SG. As Sour said, anything in suspension in the liquid will raise the SG, this includes un-fermentable solids, pulp, minerals, salts - many of these will precipitate out over time - that is why most will agree that we are "guesitmating" when we calculate ABV. I work in an industry where we use ground magnetite (a metallic ore) as a material to raise SG to 1.60-1.65 for material separation processes, I can assure you , it is not fermentable.

 

[sour_grapes]

I think bentonite would sink (eventually).

Here is the thing: I claim suspended solids (as opposed to dissolved substances) cannot change the SG much. If the suspended solid is much denser than water, it will sink. If it is much less dense, it will float. Only things that have a density close to that of water can remain in suspension for any appreciable time.

How much? I don't know. Maybe next time I mix up some Bentonite slurry, I'll check its SG.

As far as the Wiki page on Brix: That page (and nearly all sources, I think) tend to use the term "Brix" interchangeably to mean both "actual sugar content" or "apparent sugar content derived from a measurement of specific gravity, if you make the assumption that there is only sugar in the solution." The latter would change by adding other solids, the former would not. I cannot determine who "owns" the definition of Brix, i.e., whether the definition of the ICUMSA or the Normal-Eichungs Kommission or whoever else is definitive, so I cannot say which definition is "right." (This is why I am glad that homebrewers and home winemakers use SG, not Brix, despite the protestations of the professionals!)

 

[sour_grapes]

I work in an industry where we use ground magnetite (a metallic ore) as a material to raise SG to 1.60-1.65 for material separation processes, I can assure you , it is not fermentable.

Here is the thing: I claim suspended solids (as opposed to dissolved substances) cannot change the SG much.

Ooops, well, I stand corrected! (I posted without seeing the post above.)

 

[JDC]

The heavier materials like the magnetite mentioned above will settle out quite quickly, in our separation systems it is mixed by the pumping action of very large pumps - if the system shuts down the bulk of the magnetite and other materials will settle out. We use magnetite because it is recoverable using magnets after the materials are separated and rinsed. We also had some systems at some older facilities that used silica sand as the media to raise the SG. When bentonite is used in the primary fermentation it, along with other materials is somewhat kept in suspension by the CO bubbling action - once the CO bubbles quit rising and the mixing action stops the materials begin settling out.

Much like stream water, if you remove a bucket of stream water and let it sit you will notice materials collecting on the bottom & if you wait a few days you will see even more - if you had a very sensitive SG measuring device and measured the stream water's SG when you first removed it from the moving stream -vs- a few days later you would measure a lower SG on the second test (yes, a very small difference). Tap water has a higher SG than distilled water.

The largest component in most musts is the sugar, so the estimated ABV based on begining and ending SG is very close - it will be closer on mostly juice musts and will have more error on musts from fruits with a lot of non-fermentable pulps - in the end does it really matter if it is 12.5% or 12.0% ??

 

[wineh]

The largest component in most musts is the sugar, so the estimated ABV based on begining and ending SG is very close - it will be closer on mostly juice musts and will have more error on musts from fruits with a lot of non-fermentable pulps - in the end does it really matter if it is 12.5% or 12.0% ??

That makes the most sense. I am lead to believe that even the posted ABV on comercial wines can vary by as much as +/- 1% from the label. So, I'm really pretending that I know what the ABV is in my wine, so I can brag to friends. This knowlwedge is not going to change that.

 

[sour_grapes]

So, when kit the instructions call for me to stir in the bentonite before taking my initial SG reading, they want to increase the initial SG, making me think there is more sugar than there really is? Or would the bentonite (or the tiny bit of solids I could squeeze out of a grape pack) even make a measurable (visible on my SG meter) difference?

I think bentonite would sink (eventually).

Here is the thing: I claim suspended solids (as opposed to dissolved substances) cannot change the SG much. If the suspended solid is much denser than water, it will sink. If it is much less dense, it will float. Only things that have a density close to that of water can remain in suspension for any appreciable time.

How much? I don't know. Maybe next time I mix up some Bentonite slurry, I'll check its SG.

Well, I did the experiment. The instructions have you add the 15 g pack of bentonite to 2 L of water. I measured the SG before and after addition of the bentonite, and the SG rose 0.008 as a result of adding it. If we scale this to 23 L, the bentonite, if it were suspended, would raise the SG by about 0.0007. I call this less than you can reasonably tell with a hydrometer.

 

[tanddc]

It is always nice when someone lives up to their tag line.




Well, I did the experiment. The instructions have you add the 15 g pack of bentonite to 2 L of water. I measured the SG before and after addition of the bentonite, and the SG rose 0.008 as a result of adding it. If we scale this to 23 L, the bentonite, if it were suspended, would raise the SG by about 0.0007. I call this less than you can reasonably tell with a hydrometer.
__________________
Paul

I believe in evidence. I believe in observation, measurement, and reasoning, confirmed by independent observers. I'll believe anything, no matter how wild and ridiculous, if there is evidence for it. The wilder and more ridiculous something is, however, the firmer and more solid the evidence will have to be. -Isaac Asimov, scientist and writer (1920-1992)

 

[sour_grapes]

It is always nice when someone lives up to their tag line.




Well, I did the experiment. The instructions have you add the 15 g pack of bentonite to 2 L of water. I measured the SG before and after addition of the bentonite, and the SG rose 0.008 as a result of adding it. If we scale this to 23 L, the bentonite, if it were suspended, would raise the SG by about 0.0007. I call this less than you can reasonably tell with a hydrometer.
__________________
Paul

I believe in evidence. I believe in observation, measurement, and reasoning, confirmed by independent observers. I'll believe anything, no matter how wild and ridiculous, if there is evidence for it. The wilder and more ridiculous something is, however, the firmer and more solid the evidence will have to be. -Isaac Asimov, scientist and writer (1920-1992)

You are right -- it was fitting. Of course, my tag line will change in a week or so!

 

[wineh]

Sour,
Thanks, your feedback is appreciated.