Measuring Specific Gravity of Fruit musts

[mkjennison]

Hello all! I'm new to the forums and I'm working on my third batch of wine. Previous were:
-Dandelion
-Pomegranate Zinfandel (kit)

...and now I've just started a cranberry-apple, using guidance from Jack Keller's recipe. I minced the fruit and placed in a coarse nylon bag, and it's in the primary with pectinase, yeast nutrient, ascorbic acid, and some water. It's been sitting since last night. I'm going to pitch the yeast tonight.

My question is: How do I get an accurate specific gravity reading to finish the sugar addition? Am I correct in assuming that as the must continues to sit on the fruit, further sugar will be drawn out of the fruit? I don't want to overdo the sugar and make rocket fuel.

Any help is appreciated! Let me know if you have any questions.

Mark

 

[Julie]

Hi Mark,

Welcome to winemakingtalk. Get a strainer, sanitizer it and place it in the top of your must and push down slightly, I use a turkey baster to pull out the liquid that forms. You may have to do this a couple of times to get enough juice.

 

[mkjennison]

Yes; this is the technique that I used when I did the dandelion (the petals weren't contained in a bag of any kind). My question pertains to during fermentation, further sugar will be extracted from the fruit, making my initial specific gravity reading not exactly accurate. Is there a way to compensate for the remaining fruit when I pitch the yeast?

Thanks!!

 

[Julie]

How long were leaving the fruit in before you pitch the yeast? Normally by the time you pitch the yeast most of the sugar from the fruit is already in the must. Anything after that is not enough to really affect your readings.

 

[Julie]

Are you also squeezing the bag? You should be doing this daily as well.

 

[mkjennison]

Thank you for the response! Yeah, I have been pressing and squeezing the bag every few hours yesterday and today. I prepared the fruit and composited all the ingredients last night and I'm planning on pitching the yeast tonight.

Another note: I thought the pectic enzyme was going to make the fruit more jelly-like by now, but I guess not. It's definitely more squishy but there are still some good sized apple pieces. This is my first time using pectic enzyme, though.

 

[Julie]

Did you freeze you fruit? If not, the next time freeze the fruit that helps in breaking it down more. Keep squeezing the bag and take another reading before adding the yeast, that should be pretty good number

 

[mkjennison]

Thank you! I appreciate the help a lot. The cranberries were frozen and thawed beforehand, but the apples were not. I'm going to adjust the specific gravity to 1.090 or thereabouts now and keep track of it through the fermentation.

I'll remind myself next time to take a few SG readings earlier in the process, to see how quickly the fruit gives up its sugar for future reference.

 

[Brew and Wine Supply]

petic enzyme does the reverse, it breaks down the fiber of the fruit, Pectin ( used in jelly making ) will make it jell up.

 

[Stressbaby]

I looked high and low and cannot find the thread, but Luc did an experiment on the release of fruit sugars after using pectic enzyme and posted it on his winemaking blog.

 

[tucker2974]

Depending on if the fruit were frozen like he said the cranberry was and the apple was not. Pectic enzyme will have a hard time breaking down the apple if the apples aren't crushed really fine. And I'm speaking in terms of extracting sugars and most of all flavor. It would also help if the water was heated to break down the natural sugars. To sum it up ur SG reading just before yeast pitch is the number u stic by and calculate from ur FG.

Cheers

 

[seth8530]

The best way to measure the INITIAL gravity of a must tends to be with a refractometer. But they can be kinda pricy.

 

[mkjennison]

Interesting. I think the links you're looking for may be here:
http://wijnmaker.blogspot.com/2008/02/het-belang-van-pecto-enzymen-need-for.html
http://wijnmaker.blogspot.com/2008/01/avonturen-op-het-pecto-pad-deel-2.html

It compares ways to use pectic enzyme and how it affects the fruit, but not specifics on the release of sugar

Here is some specifics on how to break down apples:
http://wijnmaker.blogspot.com/2008/09/appeltje-voor-de-dorst-apple-day.html

Thanks for the reply!!

 

[Stressbaby]

Interesting. I think the links you're looking for may be here:
http://wijnmaker.blogspot.com/2008/02/het-belang-van-pecto-enzymen-need-for.html
http://wijnmaker.blogspot.com/2008/01/avonturen-op-het-pecto-pad-deel-2.html

It compares ways to use pectic enzyme and how it affects the fruit, but not specifics on the release of sugar

Here is some specifics on how to break down apples:
http://wijnmaker.blogspot.com/2008/09/appeltje-voor-de-dorst-apple-day.html

Thanks for the reply!!

mkj, I found those, but I'm pretty sure he did another study where he looked at 3-4 different fruit and measured the SG or sugar in the must over about 4 days. It was complete with graphs demonstrating the release of sugar from the fruit over that time period. I will look again this morning, nothing better to do now that the yeast is pitched, coffee brewed, and its freezing cold outside!

 

[Stressbaby]

Here it is.

 

[mkjennison]

Awesome! Great find Stressbaby. I'm not too concerned about this wine, since I allowed the fruit to sit for a day before pitching the yeast, and adjusted the SG to 1.090 right before pitching. It's happily fermenting on the fruit right now, specific gravity is 1.058 and it has a gorgeous pink color to it. I put my head in the bucket today to take a smell of it and almost knocked myself out from the CO2 that was in there

Thanks for the help, all.