Blueberry Melomel fermentation, does this seem weird?

[Brainsnap]

Hey everyone!

My girlfriend and I recently brewed a blueberry melomel, recipe as follows: 3 tsp DAP (split into two)
1.5 tsp Yeast Energizer (split into two)
9 lb clover honey from a local apiary (3 lb/gal)
1 pack Lalvin 71B yeast - rehydrated
9.9 lb total blueberries - 1.25 packs costco wild frozen and 5 lb 10 oz of naturipe Michigan fresh. Frozen overnight and thawed. all go in primary.

Method: heat water to 158 in two separate pots, one gallon water (absopure spring water) in each. add 4.5 lb honey to each pot (brings temp down to 140). cool off must to pitching temp.

Put blueberries in muslin bags and mash slightly, add to fermenting bucket and add must.

my SG calculation with just honey was 1.105 (25.5 brix) and using gotmead's mead calculator, with the blueberries it should have been approx. 1.123. After two weeks in the primary fermenting bucket (with too much headspace, but didn't open it after the first week and merely shook the blueberries around), the FG from the hydrometer was .992.

Does this seem crazy to anyone else? I was expecting the 71B to top out at around 14% abv, and i'm here with a mead that is just about 17.6%.

Where did that extra 3.5% come from? Tasting it now, it's not super 'hot' but has good blueberry flavor and comes off like a rich cabernet. My guess is that the skins had more nutrients on them than i bargained for, or this yeast is just incredibly strong.

My girlfriend detects a 'smoky/bacony' flavor, which after some reading can denote a brett infection, but I don't really taste it. Would that yeast be able to eat the extra sugars?

 

[Maylar]

Did you actually measure SG or are you just going by calculated estimates?

 

[CKuhns]

Assuming you O.G. and F.G. are accurately measured and took into account the correction to 68 dag f. Then I calculate your ABV at 15.25% , the calc I use is rough and could be off by a few 10ths. However 71B can be pushed a little and a 1% or more past published tolerance is not out of line.

Rough calc:
ABV = (OG – FG) * factor (I use 135 for no other reason than that seems to be what works for me.)
*** Factor varies from 125 to 136, depending on the source

Here is a link for reference.
http://www.meadmakr.com/how-to-determine-alcohol-by-volume/

 

[mwilcox]

my SG calculation with just honey was 1.105 (25.5 brix) and using gotmead's mead calculator, with the blueberries it should have been approx. 1.123. After two weeks in the primary fermenting bucket (with too much headspace, but didn't open it after the first week and merely shook the blueberries around), the FG from the hydrometer was .992.

think about whether the math makes sense though - you had 1.105 and added a bunch of water (and sugar)-filled blueberries. Blueberry juice gravity is a lot lower than 1.105, right? So is there any way that your blueberries INCREASED your gravity? Right, they'd actually lower it.

So your remaining sugars were within the alcohol tolerance of the yeast. I can usually get about 115 gravity points out of 71B. Beware that if you backsweeten without stabilizing it may actually ferment a little bit more.

hope that helps

cheers--
--Michael

 

[Brainsnap]

My initial and FG were measured with a hydrometer and with a refractometer (calibrated) so I am fairly certain they are accurate. The blueberry figure (actual SG) was the one that I couldn't measure accurately with either method so is all conjecture. I've been brewing beer and mead for about a decade now, but have never used a fruit addition in any beers or meads, so this part is a bit new to me.

the 15.25 percent calculation made more sense to me as well. I was basing the sugar estimates off of the gotmead calculator's (http://gotmead.com/blog/the-mead-calculator/) sugar estimates for the blueberries. It did sound high to me as well, and I'm not sure that it factors in the liquid in the blueberries either.

thanks for the advice ckuhns and mwilcox. based on my searches couldn't find an accurate source of what to expect for blueberry additions in terms of sugar v. water content. and based on you said, mwilcox, it may have been even lower than the 15.25% that i calculated.

I guess I am more curious about how gotmead came to their figures at this point, maybe just assuming fruit puree? Now to decide whether or not to backsweeten...

 

[mwilcox]

I haven't looked at the gotmead calculator, but perhaps you didn't adjust the volume for the blueberries? Even though your final volume of finished mead doesn't really change with the added berries, we have to treat it as an added volume in this calculation. Treat those berries like an equivalent puree, for a round number let's say 1 gallon of 1.050 puree added to your 3 gallons of 1.105 must. Keeping it a simple estimation like this you end up with 4 gallons of 1.091 which 71B ferments dry to around 12-13%, and lose a gallon or whatever of solids later on to get back to your finished 3g volume.
Or maybe the difference happened in some other manner...no biggie, but I'll post this in case it helps someone else.

 

[Brainsnap]

I think you may be on to something, but I wish there was a more accurate way to measure it. I didn't calculate the volume of the blueberries, you're right, but I had no idea how to calculate the liquid that might be inside or that i would reasonably extract.

I imagine a lot of it comes with experience and knowing the berries super well, and part of it is just hoping that it turns out well! (I like it so far, so its a worth experiment either way). thanks for the help

 

[Shine0n]

I've always used og-fg ×'s 130, and by my hydrometer it's fairly close.

Also, did you do a temp correction? say if you read at 78 instead of 68 or 60 then your reading will be off as well, I just bought a new hydrometer and it's rated for 60 not 68 like my other. That messed me up. lol