is my fermentation stuck?

Question

I'm a newbie working on my fourth batch of kit wine, an amarone-style with raisins from Wine Kitz. The last batch of red I did, a merlot, ended up slightly sweet, more so than I'd like although I think it was within spec for the kit. My work space is fairly cool, and the fermentation on that kit never got above 19 C or so, at or slightly below the recommended range, so I thought that warmer might help things out. Based on things I've read here and heard elsewhere, I got an electric blanket and a floating thermometer, and tried to modulate the blanket to keep things at the high end, 30-35 C. (I realize now this may have been too hot, but it was mostly low 30's.) The yeast is EC

1118 (which is supposed to go up to 35 C), starting SG was 1.110. I was supposed to rack into secondary at 7 days / SG 1.005, or wait a couple days. I finally racked last night at 9 days, SG 1.010. It's not making any bubbles, and is still sweet. The next step calls for 3 to 6 weeks of secondary. Did I get it too hot and stick my fermentation? Should I do something about it? What? And finally, I haven't dealt with the head space yet... should I top it with water or wine?

Thanks!

doug.

patrick mcdonald · Accepted Answer

I assume your starting SG was around 1.090 or so and you have advised you're now at 1.010. I really would not sweat the fact that you're not at 1.050 but check the SG every 7 days or so (3 in the first and second weeks) to see if it's progressing lower into the 0.990 territory. 1118 is a very strong yeast but I feel 9 days is a little too short to look for levels below 1.000, even with your conditions.

I dunno where you are, but the Centigrade measurements I assume you're anywhere but the US or work in automotive, science, etc. *grin* My opinion is that you should lay off the blanket you may not be able to control well. Move into your home (a bathtub not frequently used, etc.).

IF it does not progress noticeably lower in a few days, make a new batch of yeast and pitch it. I've never seen any risk in over-inoculating a batch so maybe just consider it now to allay your fears.

Ray Calvert · Answer

An OG of 1.110 is considerably higher than I would like to start. If that went to dry it would yield about 15%. Many yeasts stop at about 14%. If you want a dryer wine you probably need to use a lower OG, maybe 1.090 to

1.095

Ray

pp · Answer

EC1118 is able to ferment to 18% alcohol, so that's not a problem. The starting sg makes sense for an Amarone kit, so again, no problem. The heating might be an issue because high temperatures can cause stuck fermentations by killing the yeast prematurely. The 9 days at 1.010 sounds slow for this yeast and temps that high, so I'm inclined to say that you probably do have a stuck fermentation at this point.

First, definitely top up now to prevent oxidation - water is fine if your head space is 1/2l or so, otherwise wine is better. Then wait 2-3 days to see if the yeast picks up. If not, you'll have to try to restart.

Pp

is my fermentation stuck?

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