With modern yeasts, can you feed sugar to a must in bigger chunks?

If you are using a yeast strain to achieve a particular goal (i.e. many yeasts can have an impact on flavour, acid levels, H2S risk, etc), then it is more important to use the desired yeast and make sure you don't kill it with sugar or alcohol.

Note that it is not only the eventual alcohol level that is the problem, but the fact that too high a concentration of sugar in the must can also be toxic to yeast. So, just because a yeast can handle

Now, it tends to be the case that high alcohol tolerance goes hand-in- hand with sugar tolerance, but that is not always true. In the case of Gervin No. 3, I'm pretty sure it is rated for up to 18% alcohol and is also recommended for dessert wines (i.e. very high initial SG), so you're good to go.

In general, you need to check the specs on the specific yeast you are using, and think about what your goal is in using the yeast.

It is also a good idea to check the specs on the optimal temperature range for the specific yeast. I learned this the hard way.

I'll check on that too, thanks.

Good point.

Not good to go with the whole amount of sugar at the start, though?

I'm planning to add another 500 g of corn sugar to the (approximate) gallon (in addition to what was in the juice blend already and the

(I suppose if it doesn't work and the fermentation sticks, I could go back to the brewing shop to see if they have the yeast specifically labelled as "high-alcohol" in stock.)

Right, but I can't find a Gervin website (see next post).

Well, it probably won't kill the yeast, but it might be a very slow, sluggish fermentation. If you want the primary fermentation to be done in a week to 10 days then you'll want to give the yeast a good environment to really get going, then it'll be able to ferment the sugar additions more quickly and efficiently.

Dessert wines often finish at over 200 g/L. Most Icewines are well above this when they are bottled, but they take several weeks, even months, to ferment from the starting brix of 40+.

I couldn't find one either, but I found some write-ups on brewing shop websites and it seems to be recommended for high-alcohol and also for re-starting stuck fermentations, so you probably have the right yeast for what you are doing.

OK. If the current SG isn't very high, I'll add another 500 g (over about 4.5 litres) tonight.

Are you sure "200 g/L" is right? That's more than most beer worts

Thanks. (I've got a Gervin product leaflet, but it's at least 10 years old.)

Sure does sound high... I thought we're shooting for 1-4% residual sugar, which would be 10-40 g/L if I'm not mistaken.

I found some a table of final gravity "targets" for various categories in another old book (Mitchell, _Scientific Winemaking Made Easy_,

Dry white wine ferment to dryness Dry red wine ferment to dryness Sweet white table wine 1020 Medium sweet dessert wine 1010 Sweet dessert wine 1038

An original gravity of 1038 is 105 g/L, so a final gravity of 1038 is going to have more sugar than that (because the alcohol lowers the overall density), but not 200.

(Since I have rather more experience in homebrewing than winemaking, I found the FG 1038 quite shocking at first.)

Yesterday I forgot to measure before adding the sugar, but the sample I took while syphoning had SG 995, so I think I had waited long enough.

My big mistake with this batch was starting off with just the Pomegreat in the demijohn and coming back to add all the sugar after fermentation had started --- so I didn't have much room to add syrup (I couldn't fit all the wine in after the second addition).

Go by taste and not by numbers, those are just very rough ballpark. In fruit winemaking especially, the acids vary largely even for the same type of fruit, so taste gives you a better chance of arriving at a balanced product. That said, values around 1.040 are quire normal for dessert wines, with icewines much higher as has been pointed out - that's because the acid is so concentrated in icewine juice that very high sugar levels are needed to bring it into balance... that word again.

Pp

In Ontario, the MINIMUM allowable residual sugar in a finished icewine is 125 g/L. 180 g/L to 220 g/L is not uncommon.

Botrytized wines can get even higher still--Sauternes has been known to get over 400 g/L in the finished wine, and there have been Tokaj wines as high as 900g/L RS.

Looking for info, I've just discovered that "Icewine is a rare gift from a magical Canadian winter." Interesting.

Wow. I had no idea.

Taste is important, but I also want to avoid unexpected bottle fermentation. ;-)