WineXpert Chaptalisation @ 1.020 or less

bkisel · Jan 23, 2016

The WE kit I'm making has instructions to disolve the two chaptalisation packs (dextrose ) and add it to the primary fermenter when the SG drops below 1.020. I did that last night but this morning I find myself asking - Why not add the sugar at the start of making the wine? When I make my fruit wines I add all the sugar meant for fermentation up front, I don't add some at the beginning and some later before the wine is dry. So... What is the reason or advantage or whatever of doing chaptalisation after fermentation has started and before the wine goes to dry?

Thanx...

sour_grapes · Jan 23, 2016

Bill, we had a nice thread about yeast microbiology that led to some inferences about this question. It turns out that yeast find it much easier to digest dextrose (also known as glucose) than they do fructose. Ordinary table sugar is a combination of these two. Early in the fermentation, the yeast eat up the dextrose, and then struggle to finish off the fructose. It is even harder for them to eat the fructose when they are under stress, such as when there is a lot of alcohol in the must.

If you were to add all the sugars up front, the yeast would eat all the glucose first, and be "stuck" eating the fructose late in the fermentation, with a lot of alcohol around. But if you wait until 1.020, they will be left mostly with glucose right at the very end, which is favorable when you are trying to get them to produce a lot of alcohol.

bkisel · Jan 23, 2016

sour_grapes said:
Bill, we had a nice thread about yeast microbiology that led to some inferences about this question. It turns out that yeast find it much easier to digest dextrose (also known as glucose) than they do fructose. Ordinary table sugar is a combination of these two. Early in the fermentation, the yeast eat up the dextrose, and then struggle to finish off the fructose. It is even harder for them to eat the fructose when they are under stress, such as when there is a lot of alcohol in the must.

If you were to add all the sugars up front, the yeast would eat all the glucose first, and be "stuck" eating the fructose late in the fermentation, with a lot of alcohol around. But if you wait until 1.020, they will be left mostly with glucose right at the very end, which is favorable when you are trying to get them to produce a lot of alcohol.

Thanks! A simple, clear and informative answer. About all I can learn in one day without making my brain hurt.

Dhaynes · Jan 23, 2016

I've found from experience that it is really easy to get stuck fermentation with these kits after you chaptalize. Just Google "stuck fermentation" and you will find that these WE kits are the poster children. With the ABV already high the addition of the sugar often seems to stress the yeast to the point of no return. Temperature swings of even a few degrees also seem to cause problems. From the research I've done the best approach seems to be to keep the temp around 75 or even a few degrees warmer. Keep the temp as steady as possible. Don't add all the sugar at one time. Break the sugar up into 3 parts and add one third at a time every 1-2 days. Also, if it still gets stuck do not resort to heroic measures to try to restart it. That will likely have a negative effect on the taste. Just stabilize the wine and clear it. They are desert wines so they are suppose to be sweet anyway.

TallTexan · Jan 23, 2017

dextrose appearance

I pitched a double batch of Chocolate Raspberry Dessert Wine (two WE kits in one primary) this weekend. In looking over the ingredients included in the kit, I noticed that the powdered dextrose( for adding later for chapitalization) included in both kits has a speckled appearance...the white powder has some light tan/brown speckles throughout the package. The packages are well sealed. I've made this kit a couple of times before and don't recall this coloration pattern. Has anyone else noted this with their dextrose? Should I be concerned?

Grabo · Jan 23, 2017

TallTexan said:
I pitched a double batch of Chocolate Raspberry Dessert Wine (two WE kits in one primary) this weekend. In looking over the ingredients included in the kit, I noticed that the powdered dextrose( for adding later for chapitalization) included in both kits has a speckled appearance...the white powder has some light tan/brown speckles throughout the package. The packages are well sealed. I've made this kit a couple of times before and don't recall this coloration pattern. Has anyone else noted this with their dextrose? Should I be concerned?

Yup, I had this with my Amarone kit. All the sugar dissolved properly and fermented completely for me on that kit. It didn't seem like anything to worry about to me, as it looks more like a mixture of sugars. On one of the Amarone threads, a group of people pointed this out as well, so yours isn't different from what we have been seeing.
Link to the thread