Can water chemistry or ph cause fermentation off flavors?

[hardrain]

Hey all, trying to track down a ripe apple flavor I'm getting, most recently in english-style ale yeasts and even a saison...it's consistent across a couple of different yeasts.

I'm wondering if a lack of certain minerals or higher-than-desirable ph readings of wort can cause a yeast to stress, and potentially be causing this apple-like flavor.

I've not yet gotten my well water report yet, but have just dove into the bottled water I've been using (making up ~80% of my water during brew day, I still use a little well on sparge) and noticed on the bottled water report that mineral counts are way low compared to what I see as recommended for water profiles, most recently (in ppm):

calcium - 7
magnesium - 2
sodium - 6
sulfate - 0
chloride - 3
bicarbonate - 34

In a (poorly understood) effort to reduce alcolinity, I've actually been cutting my initial dough in water with 50% distilled water, so my actual boil water is about half those numbers, plus 20% tbd well water.

I've ruled out temperature and yeast count as the issue -- I'm onto mash ph (I've been in the 5.5-5.7 range lately) and simple water issues. Is there any literature on a lack of minerals causing yeast to stress?

If not, could a higher-than-desirable post-boil ph also cause issues (something I think a lack of calcium has been causing for me, although I'm now getting serious about using acids to appropriately fix the mash)? I've heard of high ph causing instability and potential infection, but not actual stress flavor production from yeast.

 

[dsniegocki]

In my relatively primitive understanding, yes fermentation pH has an effect but mash pH is more relevant with regard to conversion than flavors per se. Your mineral numbers seem low and my guess is that is not a contributor to a ripe apple flavor. My first guess for this type of flavor (especially since you didn't mention it) would be your fermentation temperature... how do you currently control ferm temps?

 

[hardrain]

It's possible the fermentation is generating so much heat internally that my controller is way off.

I guess I could test by opening the lid and taking internal readings occasionally.

 

[dsniegocki]

You could also try a thermowell, not sure if you mean plastic carboy or plastic bucket, but I think they're available for both. Would give a better reading than the side of the fermenter, and certainly better than opening the lid.

https://www.brewershardware.com/12-Weldless-Thermowell-WLFTW12.html

How is your yeast health? Is it dry or liquid? Do you hydrate dry/perform a starter on liquid?

 

[giraffe]

Calcium that low will impact yeast health. It should be at least 40-50ppm for ale yeast (lager yeast is more tolerant of low calcium).

Adding calcium chloride or gypsum would be a better way to reduce alkalinity with water that soft. Id download bruin water since you have a water report for your mash water and add cacl2 or gypsum to hit a mash ph of 5.4-5.5. (which will also both add calcium.

 

[hardrain]

You could also try a thermowell, not sure if you mean plastic carboy or plastic bucket, but I think they're available for both. Would give a better reading than the side of the fermenter, and certainly better than opening the lid.

https://www.brewershardware.com/12-Weldless-Thermowell-WLFTW12.html

How is your yeast health? Is it dry or liquid? Do you hydrate dry/perform a starter on liquid?

Interesting, using plastic buckets, guess I could install one in the side of a bucket and keep an eye on that.

Yeast health I feel good about -- 2L starters, cold crash 2-7 days and decant. Only catch there is I wonder if my well water is stressing out the population in the starter...I'll try using bottled with water adjustment to get calcium up...or is that overkill?

Re the calcium, I'll give that a shot on brew day as well.