Yeast at high altitudes

[lilvixen]

Does anyone know if yeast has an issue fermenting below 1.000 at high altitudes or in desert climates or some other possible environmental issue?

I live at 4500ft elevation in a high desert climate. I've made four 10L wine kits, four 16-18L wine kits and one fresh peach wine with various yeasts: EC-1118, D-254, BM4x4, and D-47. Every one stopped between 0.997 and 1.000.

Using a Brew Belt, and I keep the white wines at 68-74*F and the reds at 75-80*F during primary. The wines sit 6-10 days in primary and then 3 weeks in secondary. Secondary is generally without the Brew Belt, and is 67-72*F depending on the time of year.

The SG at the time of pitch is 1.080+ for reds before skins and 1.090 for whites, so I don't believe it's the hydrometer calibration, plus I've gone through a few hydrometers now, and none have reported a wine lower than 0.997.

So it's not the type of yeast or the fermenting temperatures, I don't believe it's the hydrometers because the starting SG is reasonable, and it's not just kits, because the fresh peach wine stopped at 0.999. Oh, and generally, the temperature at pitch is within 2 degrees of the temperature at final reading, so it's not a temperature correction thing.

I'm at a loss here, CC, RJS, and WE instructions say wines should stop below 0.996 and 0.998 for white and red, respectively, and I'm lucky to get below 1.000. Plus, I read about other kit makers that get down to 0.992 or 0.994. My wines taste fine, so that's not a problem, but I still don't understand why mine stop at just barely dry. For peace of mind, I use sorbate if the wine stops at 1.000, but I chance skipping it at 0.998 and below, with a coin toss and "do I feel lucky today" for the one that stopped at 0.999.

Any thoughts? Does it matter? Should I care? Am I missing something? Is it my house? Is it me? Am I overthinking this?

 

[ibglowin]

I live at 7000ft. No issues. If I had to take a WAG I would say your Hydrometer is off a few points. Its only a $5 tool. Test it in a graduated cylinder filled with distilled water and see what it reads. It should be 1.000 if not then either add or subtract any offset you find from 1.000 to your wine samples.

 

[Cellar_Dweller]

Cat,

I'm at just over 5000' in a fairly dry climate and am able to get down to 0.994 s.g. on reds, but I'm not sure that altitude is not a factor. That is not to say I haven't experienced some of your problems though. I currently have a C.S. sitting in a barrel at about 0.998. Just off dry, but a little too sweet for my taste. My wife loves it however. Nothing terrible, but a little disappointing to the wine maker.

The problem with completing fermentation only started when I started getting kits with grape skins, and I started substituting yeasts! So my analysis is somewhat confounded, but I feel that it is more the yeast. Altitude may make the whole process a little more sensitive, because if it were a pervasive problem, I think that we would see a lot more posts on this subject.

Greg

 

[lilvixen]

I live at 7000ft. No issues. If I had to take a WAG I would say your Hydrometer is off a few points. Its only a $5 tool. Test it in a graduated cylinder filled with distilled water and see what it reads. It should be 1.000 if not then either add or subtract any offset you find from 1.000 to your wine samples.

I haven't validated the calibration of the latest hydrometer, I'll check it tonight. I have checked previous ones, and they reported close enough to 1.000 in room temperature tap water that I haven't worried about correction. If the calibration is off by 0.005+, wouldn't that consequently mean that the kit starting SG is lower than expected?

The problem with completing fermentation only started when I started getting kits with grape skins, and I started substituting yeasts! So my analysis is somewhat confounded, but I feel that it is more the yeast. Altitude may make the whole process a little more sensitive, because if it were a pervasive problem, I think that we would see a lot more posts on this subject.

I wish I could say mine were limited to skin kits with yeast swaps, but a CC Sterling Sauv Blanc with EC-1118 stopped at 1.000, a WE Selection Chardonnay with D-47 stopped at 0.997, and the CC Sterling Pinot Grigio with EC-1118 I racked from primary yesterday isn't looking any more promising. The skins kits stop at 0.997-0.998.

 

[ibglowin]

Wait so your splitting hairs on your fermentation seemingly only reaching ~0.998 instead of ~0.994 but your willing to ignore about the same error in your Hydrometer calibration check?

I haven't validated the calibration of the latest hydrometer, I'll check it tonight. I have checked previous ones, and they reported close enough to 1.000 in room temperature tap water that I haven't worried about correction. If the calibration is off by 0.005+, wouldn't that consequently mean that the kit starting SG is lower than expected?.

 

[lilvixen]

Wait so your splitting hairs on your fermentation seemingly only reaching ~0.998 instead of ~0.994 but your willing to ignore about the same error in your Hydrometer calibration check?

When I tested the hydrometer in room temperature water, it read 0.999 or 1.001, which could also be the margin of error reading the meniscus. It wasn't reading 0.995 or 1.005. If it had, yes, I would have adjusted subsequent readings for the offset.

 

[AZMDTed]

I would love to find a hydrometer with the scale engraved in the glass. On my current batch before I pitched the yeast I calibrated and my hydrometer was off by .009. When I checked the wine at the end of primary the same hydrometer was off by .004. Color me frustrated.

I think what happens is that as I wash and rinse the hydrometer my movements, read that agitating and shaking, shift the paper inside with the scale on it. So now I know that I need to calibrate it each time. Very frustrating. Last year I didn't calibrate much and I was easily getting readings at .992. After paying more attention to calibration I'm seeing that I'm lucky to get it down to .998 and that's after six weeks of extended maceration fermentation.

 

[Johny99]

I'd look for a low range hydrometer. With the larger scale you get a much better reading. They are a bit costly, I think mine was $40, but I think worth it. My guess if fermentation has stopped and the taste is ok, it might just be the hydrometer. You can also do a Clinitest sugar test, but I've given that up for the second hydrometer.

And yes you might be overthinking it, but that is what we all do! We are obsessed::

 

[lilvixen]

I checked my current hydrometer, and in room temperature water (69*F currently), it reads 1.002, which is only a 0.001 error with the temperature correction according to the little paper that came with it. While that lowers the final SG of my wines a smidge, they're still finishing above what the instructions say they should finish at, and above the magical 0.992 and 0.994 SGs.

For my curiosity, at what error-corrected SG is it considered "safe" to skip the sorbate? The existential question: how dry is dry?

 

[Johnd]

For my curiosity, at what error-corrected SG is it considered "safe" to skip the sorbate? The existential question: how dry is dry?

Not sure there's a standard set in stone, and some depends upon your risk tolerance, but for me, if it gets into the .998 or lower range, that's good enough.

 

[ibglowin]

As long as it is <1.000 your safe for the need of any sorbate. Do not get hung up trying to reach the magical 0.994 each time as it does not always happen.

 

[lilvixen]

Thanks, guys. My exposure to making wine includes this forum, kit instructions, and the occasional googled page, so my knowledge is likely skewed.