Help - mysterious acidic flavor in raspberry mead

[sarah6]

Hi all,

It's my first post, and I'm desperate for any advice you can give me! This is going to be pretty long-winded, but I hope that erring on the side of too much info, rather than too little, will give you what you need in order to formulate some advice for me.

I've got a 5-gallon batch of raspberry mead going:

15 lbs. local wildflower honey
5 gal. commercial spring water
1 smack pack Wyeast Sweet Mead Yeast #3184
4-5 lbs. frozen organic black and red raspberries from my backyard
Specific gravity at start: 1.051
Today's specific gravity: 1.025

Heated the water and stirred in honey in batches, added hot honey/water mix to carboy, added raspberries, let cool, pitched yeast, stoppered carboy with airlock. After a few days, it became apparent that nothing was happening, so on the advice of a meadmaking friend I bought another pack of the same Wyeast and pitched it in...and we were in business. Shoved the carboy underneath the dining room table to get it out of the flow of traffic, and walked away.

Okay, to be honest, I probably walked away for too long. I mixed the mead on 12/17/12...and racked it today for the first time, nearly 6 months later, onto 4-5 more pounds of frozen homegrown raspberries. (I've made a couple of one-gallon batches before that sat on the yeast for almost a year, and they turned out to be fantastic, so I didn't think it would be an issue.) I also sampled it for the first time, and it has a nice raspberry smell, a beautiful translucent deep rosy color, a very nice sweetness, no discernible alcohol taste, and a pleasant fruity/honey flavor...but it also has a surprising sourness. It reminds me of a Flanders sour brown ale--that level of sourness, but with enough sweetness to balance it out. It's kind of pleasant, actually, but I know it's not right. I stuck a sample in the freezer for about 20 minutes, and the acidity seemed to be somewhat tamed by the cold...although maybe that was wishful thinking at work? :/

When I racked it, I didn't notice anything "off"-looking--no floating fuzzy patches, tendrils or films. There were a few floating raspberries around the edges, and some raspberry-colored scum clinging to the glass. There was about a 6-inch head space between the mead and the stopper--not sure if that was because of evaporation, or because when it was mixed a lot of the raspberries were floating on the surface, or because I didn't add enough water to begin with.

So...what do you suppose has gone wrong? And more importantly, can this mead be saved? My aforementioned meadmaking buddy suggests I throw in some light roasted oak chips to encourage the flavors to blend...is that worth a try? Are there any other methods to reverse the development of vinegary flavors in mead? Or is it only doomed to get worse?

I made it to serve at my wedding in September, so I'm kind of panicking.

Okay, not "kind of". I'm seriously in full panic mode.

Thanks in advance for anything you can give me. If you need any additional info, just ask and I'll try to fill in the blanks. I really appreciate this forum!

~s

 

[akueck]

That OG reading sounds off, although it's not super important for the current discussion. I'm guessing things weren't mixed completely? Most likely you started around 1.080-90.

Anyway, given the current SG of 1.025, I'd say your mead is stuck. Even the sweet mead yeast should be able to take this one much lower. Sounds like you didn't add any yeast nutrient, do any post-pitch aeration, etc?

You mention the sourness and Flanders beer, but at the end you say vinegar. Does it actually taste like vinegar (acetic) or is it just sour? Do you know the current pH?

My guess is that the pH of this one has gotten a bit low. That combined with not enough nutrients has given you a tart, stuck mead. Check the pH and we'll see if that is part of the problem.

 

[WVMJack]

The first thing to do when you are panicking with a carboy of mead in front of you is to leave it alone! OK, does it still have a lot of gas? You have not added enough fruit to affect the acid very much with only 2 lb/gal unless your fruit was very unripe which I doubt. So you probably just have gas, degass it and see if that helps a little. Your raspberry will take a little bit of oak very well, just dont add to much oak with so little fruit. This is supposed to be a relaxing hobby right . WVMJ

 

[sarah6]

Thanks for your quick replies, guys.

akueck, it's entirely possible that there was an incorrect OG reading either then or now, although I can attest to the fact that there is pretty much no detectable alcohol flavor. And you're correct, there was no nutrient, aeration, etc. I'll have to run to the homebrew store tomorrow and pick up whatever it is I need to get in order to test pH (I assume that's where I'd go to get that sort of thing?). It's definitely not as sharp tasting as straight vinegar, or even salad dressing...it's just slightly sharp, much like a sour ale. I'll get back to you with a pH reading ASAP.

WVMJack, Yes, the raspberries were quite ripe. Also, I don't know what you mean by "degassing". Today I racked it to a clean carboy, added more raspberries, and put a clean air lock in the top--that's all. If there's something else I should try, let me know and I'll do it right away!

Thanks again, you guys!

~s

 

[fatbloke]

We often add a fruit element to a mead because we like the original/natural flavour of the fruit.

What we don't expect is the change in flavour when fermentation takes place.

Raspberries are strange because while they're not always sharp tasting, once the fruit sugar starts to disappear, the taste can becom3 very sharp and the flavour from the fruit very dominant.

The yeast convert the sugars into alcohol and CO2. Which is what Jack was alluding to. It's in the form of carbonic acid initially but as the concentration rises it passes out of the liquid as gaseous CO2. Now if you read the NewBee guide (left hand side yellow dialogue box) there will be mention of aerating the must by stirring particularly in the early stages of ferment (for yeast development/health) but it has a side effect, in that it also mixes up any sedimentary material and fruit particles, which create "nucleation points" for the carbonic acid/dissolved CO2 to attach to, and creates bubbles, lots of them.

This can be a very quick reaction and depending on the type of container/fermenter vessel you can end up with an eruption/fountain of mead (buckets are better to do primary fermentation especially with fruit batches). Its also why, if the ferment is proceeding well, with fruit batches especially it can sometimes foam enough to bubble up out the airlock.......

So as already suggested, nutrient.......well actually the tan coloured powder one like Fermaidk or fermax or similar, something to test pH (and something to reduce it, potassium carbonate if possible).

And of course, don't make any promises about having this ready for September. As it's likely it won't be ready. Meads can take a long time.

Even making a JAO would be pushing it given that time frame.........

 

[sarah6]

You guys may be onto something. I just went into the dining room to find mead erupting out of the air lock.

~s

 

[Chevette Girl]

Heh, evil mead! My best guess is that the raspberries are less acidic than your mead and the addition of the berries raised the pH enough for the yeast to be back in action...

 

[sarah6]

So, 24 hours later, I have been to the homebrew store and come home with a pH test kit and some light oak chips.

They didn't have Potassium Carbonate, but they had Potassium BIcarbonate, which the clerk told me was "pretty much the same thing," so I also bought some of that.

According to the pH test strips, the acidity of the mead is somewhere between 3.2 and 3.6 (but it looked closer to 3.6). It really does taste less acidic today--the acid is out of the way enough that I can taste more berry, honey, yeasty flavors. The panic is beginning to subside.

So...what's my next step? Add nutrient to encourage the yeast?

Thanks for all your help,

~s

 

[Chevette Girl]

Well, yeast is happy at 3.6 to 3.8 so maybe it's not the pH...

Has the specific gravity changed? If the mead was attempting to escape through the airlock then it's likely kicked up again, if it has, you probably just want to stand back and let it do its thing.

 

[akueck]

Could just be the flavor of fermented berries as FB said. It does take a bit to get used to the flavors of things when all the sugar is gone. pH of 3.6 is fine.

 

[WVMJack]

DO NOT just add any powder to your mead, you will get a valcano! Your strips not very reliable. Carbonate and Bicarbonate are I dont think the same thing, better check it out before using. You have done nothing to resolve your panic, but the yeast did WVMJ

So, 24 hours later, I have been to the homebrew store and come home with a pH test kit and some light oak chips.

They didn't have Potassium Carbonate, but they had Potassium BIcarbonate, which the clerk told me was "pretty much the same thing," so I also bought some of that.

According to the pH test strips, the acidity of the mead is somewhere between 3.2 and 3.6 (but it looked closer to 3.6). It really does taste less acidic today--the acid is out of the way enough that I can taste more berry, honey, yeasty flavors. The panic is beginning to subside.

So...what's my next step? Add nutrient to encourage the yeast?

Thanks for all your help,

~s