Taste Dilemma - first time with real grapes

[ILWIIA]

Good afternoon all - this is my first post, but I want to first extend a significant thank you to each and everyone's contributions to this forum. I started making wine from kits about 15 months ago, and recently transitioned to a batch from grapes (10 gallons of frozen Cabernet must from Brehm to be exact). This forum and all of your individual contributions have been invaluable. I would be far behind it if weren't for everyone's insight.

Anyway, my current dilemma - it involves a lingering taste/sensation that I cannot identify. Some background - I purchased 10 gallons of Cabernet Sauv. frozen must from Brehm's Plum Grove vineyard. I let thaw over 4 days, and pitched yeast on 12/26/15, when the temperature was roughly 66*F (I created a yeast starter on 12/25/15 in the evening, with 2 packets of RC-212, 250mL of wine juice from the must, 1/4 tsp of Wyeast nutrient, and pitched the yeast starter the morning of 12/26/15 after it sat overnight). The starting Brix was 24.5/specific gravity was 1.103. Unfortunately, at that time I had no way of measuring TA or pH, but Brehm's log indicates the TA was 7 g/L with a pH of 3.34, and a YAN of 60mg/L. I did not add any KMeta pre-fermentation, and I fermented in stainless steel. I fermented over the course of 7 days, punching down several times per day with sanitized stainless steel potato masher. At the end of day 3, I added 1 tsp of Wyeast nutrient. At the end of day 7, the brix was 0, and so I chose to press, and let the primary fermentation finish in the carboy. I pressed everything I could out of the grapes until the cake was nice and firm. When pressing, I mistakenly pressed some seeds into the carboy (but they were only exposed for the brief period of time until I racked off gross lees). Side note, temperature reached 85*F on day 3 and I tapered down to high 70s/80*F for the remainder of primary in stainless (days 4 - 7). At this point (i.e., press), the wine had a sweet taste and was actually fairly smooth for being so "new". On day 9, 2 days after press, I racked off the gross lees into a new carboy and added Viniflora CH-16 malolactic culture. I did not top up at this point, as I hoped the remaining fermentation would produce some sort of protective layer. The level in the carboy was above the shoulders but several inches below the neck. I also added two french oak staves, and set the heat wrap to maintain at 70*F. Over the next several weeks I stirred multiple times per week, and had visible bubbles rising up through the wine and popping of the airlock. I also tasted once or twice and could taste a noticable change to the wine, it got much smoother, which I would expect based on what I've read regarding malolactic fermentation. After five weeks since pitching yeast (12/26/15 to 1/31/16), I racked off of the oak staves into a new carboy, and I topped up with 1/2 bottle of Kendall Jackson 2012 Sonoma County Cab. One week later (2/6/16), I performed a malolactic test and I couldn't tell if it was complete or not (it seemed complete, but I'm a noob, so I left it). Fast forward about two more weeks, for a total of approx. 8 weeks since pitching (2/21/16) I did a second malolactic test and the results were nearly identical, there was not much of a visible sign of any malic acid, with strong spots for tartaric and lactic.

At that point, I decided it was done with malolactic (I included images for both MLB tests) and I racked it into a glass carboy and added 1/4 tsp KMeta (dissolved into distilled water and slowly stirred into wine). I also tasted (prior to Kmeta addition) and this is where the dilemma comes into play. The wine smells fantastic, strong hint of oak (that will hopefully calm with age), no off odors whatsoever. Taste - tastes full body, strong tannin (significant dry mouth sensation) and hint of fruit, oak comes in at the very end after I immediately swallow. However, after about 5-10 seconds of "digesting" the swallow, there is a strong tart sensation, almost metallic sensation, that lingers for quite some time. I should also mention by this time I acquired the tools to test for pH, TA, and free SO2. pH was 3.68 (after boiling and letting cool down to room temperature), TA was 7.00 g/L, and free SO2 is 47mg/L. After testing the free SO2 and realizing it was a little light for the pH level, I added the necessary KMeta to bring it up to around 67 mg/L.

Anyone have any idea what I am tasting/sensing? Is the acid balance out of whack? Did oxidation occur? Did I leave it on malolactic too long, or too brief? I find it bizzarre that up and until 4/5 weeks into malolactic it tasted awesome (smooth/buttery), and then an extra couple weeks and now it has this lingering odd sensation. Being new to this, I have scoured the internet trying to figure out what could be wrong to no avail. Any help or suggestions is much appreciated.

Thank you,

Zach

 

[ceeaton]

Take it from another newbie, you are tasting a very very young wine. Your doing all the things right, now just leave it to age. I have the same with my Dornfelder batch from grapes this fall, plus there is a little bitter bell pepper aftertaste mixed in. I'm at almost six months, and those flavors are smoothing out, but I know patience is a virtue. Now comes the time for both of us to practice being virtuous.

PS. it is good to do an MLF test when you first pitch, gives you something to compare it to.

Edit: And excuse my lack of manners, welcome to WMT!

 

[stickman]

Welcome Zach,

I've used the same batch of fruit and have not noticed any metallic taste, but that doesn't mean there is anything wrong with your wine, as Craig indicated it may be a young tannic co2 rich wine that needs a bit of time to relax.

I'll make a few comments as I have significant experience with this frozen fruit.

I prefer pitching the starter at 55F to reduce the impact of the wild yeast and microbes that propagate quickly during the thawing of the must, this is especially important when not using sulfite in the must. By the time the must is at 66F, unless the starter is large, it will have a difficult time becoming the dominant strain.

The brix and TA values provided are only an average and individual pails will vary, I have seen reported values of 24 and measured values at 26 brix.

The must nutrient level was very low as indicated 60ppm YAN, I calculated the required nutrient addition for the two pails combined at 16 grams of Superfood and 20 grams of DAP; based on your description of no off odors, you did well.

My preference is to kill off the malolactic bacteria with sulfite a few days after the chromatogram shows complete and butter is not excessive. Allowing the wine to remain at 70F with a heat belt well past the end of malolactic without sulfite, can cause a little volatile acidity as the bacteria consume citric acid and then any residual sugar that is present. As long as the VA threshold isn't crossed, it's not entirely a bad thing, it just requires more time for those things to combine harmoniously with the wine.

All that being said, my guess is that you're tasting a combination of natural acidity, tannin, co2, and volatile acidity, which have an additive effect on each other. Those grapes are mountain fruit from 1700' elevation, high in tannin with a high capacity for oxygen; time with oak exposure should smooth things out.

Let us know how things work out.

 

[NorCal]

I think the stickman nailed it. I attribute it to the "winemaker roller coaster". Great feelings of doing all the right things, in the right order, at the right time and things smelling and tasting great. This is quickly followed by off smells and tastes that are no better than that cheap bottle of wine your cheap neighbor drinks. But, you hang in there, give it time, nurse it back to health and the end result is something you are beaming about.

 

[ILWIIA]

Thank you Craig, Stickman, and Norcal - appreciate the quick, insightful responses. Being new, it's hard to decipher what is a "young" taste, that will subside with time, versus what is "off" taste that should not be there. Also, I will definitely take your recommendation going forward and pitch yeast sooner in the thaw process.

I will absolutely let this batch grow older before jumping to a conclusion that it went bad. However, I do have a few follow-up questions based on your inputs:

1. If there is VA going on, is there a way to formally test for that? How do I know if I've crossed the "threshold" referenced above? If I have crossed the threshold, would there be other sensations/odors than just the lingering sensation I'm tasting? And, if I have crossed the threshold, is the wine considered ruined?
2. Re: Oak - since I've already introduced the oak staves for a period of several weeks, is that all the oak you refer to? Or, do I need to expose this batch to additional oak to treat any of the aforementioned issues?

Again, thank you all for your quick inputs. Now that I have an account on here, I will strive to provide more input to this community other than just browsing/reading like I've done the past 15 months. And, I apologize for the overload of thoughts/questions.

 

[heatherd]

Welcome to the forum!

 

[stickman]

There is a VA test rig , Cash Still, but it is fairly expensive and difficult to justify for home winemaking purposes. I cobbled one together several years back and ran a number of tests on my wines as well as some commercial wines, and it was enough to prove to me what I was tasting. The threshold varies depending on the wine and the taster, as well as what microbe generated the VA, but the generally accepted threshold concentration is .07g/100ml based on acetic acid. A typical red wine will usually have less than .04g/100ml, but I have measured some commercial wines at .06g/100ml. Some winemakers believe that a little VA is a benefit as it can add some spice, but again it all depends on your perception. For my wines, when the wine approaches .07, my perception is increased heat and alcohol, it does not taste like vinegar at that low level. In 2007, at around 9 months of aging, I had a Cab in barrel hit .09 before I knew what happened, it was a hard lesson learned, the wine went from stellar to poor. The barrel was topped up and sulfited, but the wine was high PH and had slight residual sugar, nothing you could taste, and that's all it took. If the VA is produced by malolactic bacteria consuming residual sugar there usually wont be noticeable ethyl acetate (nail polish), but if acetobacter is involved you'll start to notice ethyl acetate in the nose. Commercial wineries have the option to reduce excess VA using reverse osmosis, but for home winemaking blending is the only option, and it's not very practical because the blending wine already has a normal amount of VA present, so the volume needed to make an improvement is much more than you might expect.

Oak is a personal preference, I usually leave the wine on oak staves until ready for bottling, but it depends on how much you put in the wine, so go by taste.

Relax and keep the sulfite levels up and maybe rack in one month and then again at three months and go from there.

 

[ILWIIA]

Greetings - an update here.

Thank you again for providing previous feedback. I want to provide an update and get some thoughts from the group. The wine previously discussed has been aging in glass carboys for roughly 18 months since last discussion. Tested the wine yesterday, ph = 3.8, ta = 7.2 g/l, free so2 = 79ppm.

Anyway, first thing I want to bring up (see attached image) is there is a noticeable white/yellow ring where the wine meets the air. I've racked and sulfited roughly every 3 or 4 months, and this just started showing up within the last few months. Carboy has been kept at roughly cooler than room temperature for most of the aging (roughly 65 - 68 degrees) in the basement, maybe hitting mid 70s once or twice due to heat waves (basement isn't fully below grade unfortunately).

Second thing, is the sensory testing we did. Wife, friend and I took a large sample (75ml approx) yesterday, and we swirled and swirled and analyzed. Deep excellent color, clear, no browning, etc. Smells like a cab, not overly fruity, no off odors, can pickup the oak from the staves I used during initial process. Tastes like a cab, goes down smooth, slighly velvety, but aftertaste is where I'm having an issue. after maybe a second or two of digesting the sample, there's a bitterness (not overwhelming), but it's present and it's not something i'm used to in a cab. Wife and friend said it was pleasant, and although the bitter bite at the end (wife thought it was sour, but friend claimed it was on the back of the tongue and slight bitter, so i'm leaning toward bitter, but i could see why my wife considered it sour).

Any ideas on what I'm seeing with the ring, any ideas what i could be tasting with the bitterness or sourness? Are the two related? Any insight and help is much appreciated. I want to kick this so I can bottle this batch and get it on its way.

Thanks!

 

[stickman]

Unfortunately there are many things that can cause bitterness. I'm a little surprised that your pH is now 3.8, but the TA is still up at 7.2 g/l. The pH increase is not surprising as tartrates drop out during aging, but the TA should have dropped accordingly. Has your meter been calibrated?
The fact that you first noticed this bitterness after ML does suggest possible VA, or other microbial influence, but again, TA, VA, tannins, co2, all work together to exaggerate harshness, so it is difficult to say without a lab test.

Bitterness can sometimes be caused by tannins, so a bench trial fining with egg white may be worth while to see if reducing tannin will help.

I'm not sure about the yellow ring, though sometimes a white ring occurs just after racking and adding sulfite.

You can always bottle it and let it go in the cellar, in most cases it changes for the better.

 

[ILWIIA]

Good question on the calibration - I calibrated the ph meter (I have the Vinmetrica SC-300 kit, so it has both ph and so2 electrode). I did not calibrate the so2 electrode when i measured TA yesterday - should I have done that?

 

[stickman]

I don't have direct experience with the Vinmetrica, I just wanted you to be sure to follow the owners manual.

 

[Ajmassa]

1. If there is VA going on, is there a way to formally test for that? How do I know if I've crossed the "threshold" referenced above? If I have crossed the threshold, would there be other sensations/odors than just the lingering sensation I'm tasting? And, if I have crossed the threshold, is the wine considered ruined?
And, I apologize for the overload of thoughts/questions.

Remember other people read these threads. And your asking great questions. No need for apologies. You are detailed and have already helped me by this thread.

The barrel was topped up and sulfited, but the wine was high PH and had slight residual sugar, nothing you could taste, and that's all it took. If the VA is produced by malolactic bacteria consuming residual sugar there usually wont be noticeable ethyl acetate (nail polish), but if acetobacter is involved you'll start to notice ethyl acetate in the nose. Commercial wineries have the option to reduce excess VA using reverse osmosis, but for home winemaking blending is the only option, and it's not very practical because the blending wine already has a normal amount of VA present, so the volume needed to make an improvement is much more than you might expect.

Stickman, the info here is extremely helpful and informative. But also alarming, since I hadn't had a shred of concern or any knowledge really about VA aside from looking up the definition once before.
Would you say this is common? More specifically in a batch with high ph 3.9 undergoing MLF with a possibility of some residual sugar .999?
And if these factors raise the potential are there any preventative steps to take to make sure VA doesn't happen or doesn't continue? Can't sulphite just yet. Wasn't planning on adding tartaric until MLF completion but maybe I should? The lab that does testing near me has about 12 different items, none of which are VA.

 

[stickman]

The issue with VA is real, and yes, a wine with pH of 3.9 undergoing MLF with residual sugar is a risk that needs to be watched carefully. The high pH will cause the ML fermentation to go quickly, and the high pH also shifts the bacterial selectivity towards Lactobacillus or Pediococcus, which can easily produce off flavors including VA.

The primary prevention is lower pH, and using a commercial bacteria strain, though we're not always lucky enough to have the low pH. It is also critical to run a chromatogram to determine when the malic is gone, as bacteria usually consume the malic acid first even if sugar is present; consumed second is citric acid, and then sugars including nonfermentable sugars like pentose. So once the malic is gone, there is a window of opportunity to add sulfite and stop the ML fermentation before the bacteria start consuming other compounds.

If you have been allowing oxygen to the wine while stirring during ML, the oxygen will cause the bacteria to initially favor the production of diacetyl (butter), and adding sulfite while the wine contains diacetyl will lock it in, desirable in some whites, not so desirable in reds. With red wine, if you smell excess butter, wait a few days until it is consumed before adding sulfite. Without sulfite, continuing to allow oxygen contact to the wine near the end or past malic consumption, will cause the bacteria to favor VA production from citric acid and the remaining sugars.

 

[mainshipfred]

There is no calibration required for the SO2. When testing the Ph and TA make sure the sample is completly degassed. CO2 in the sample can cause off or inconsistent readings. Whether it's necesary or not I calibrate every time I use it and sometimes depending on how many tests I take recalibrate more then once a day. for both tests make sure to clean and blot the probe after each use.