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The Tale of Two Yeasts

2016 October 16

 

I am a lover of careful observation of fermentation kinetics.   Over many years I have learned and recorded my observations and used that experience to become a better winemaker.   Every year can be different.   Some factors which makes that so include Brix Level, Yeast Selection, Ambient Temperature, and Berry Size.

I have experienced ultra fast hot ferments and cold ones as well.  I am a fan of getting at least to mid to upper 80s.  With one half ton batches or greater obtaining that level of heat is not usually a problem.  However as all Winemakers will tell you, “Shit Happens”.    Sometimes, usually earlier in the season when Winery Temps are in the Mid 70s to low 80s ferments can get too hot.  And what is too hot?  Well if you read the manufacturer’s yeast charts anything over 88 is dangerous.  In actuality getting to the mid 90s is standard practice with some winemakers and many yeasts have no trouble in that temperature range.  Yet is seems when ambient temps drop to the 60s the risk of getting over 90 is pretty slim.

This year my goal was to go 14 days between Crush and Press.  Truthfully this was not some artisanal decision.  All I really want to accomplish is having the Team skip a weekend between the Crush and Press.   In order to accomplish this I asked Frank Musto of the Musto Wine Grape Company to deliver the grapes to me as cold as possible.  In the past I have asked Frank to leave my grapes out of the Cooler the day before so I could get a jump start and not have to wait for the temps to rise for the yeast to get busy.  This was when I wanted to finish in 7 days.

So the grapes arrived and after crushing they were 48 degrees.  Assuming you can get your grapes delivered at 48 degrees you can forget about all you read about using Dry Ice and Ice Bombs.   If you insulate your vats you can expect to be at 63 degrees and no higher in 3 probably 4 days.  So if you interest is in Cold Soaking that should be enough time without using other cooling methods.

Then there is the story about Nutrients.   The latest craze it seems, who started it I have no idea, not to use Fermaid K.  Why?   It contains DAP.   Me? So What?  I have written about DAP fear before but even then Fermaid K was ok.   It is as if DAP is considered the worst thing in the world a winemaker can use.   Never mind Trucks deliver thousands of pounds of the stuff to California Wineries every year.   It has it place and Winemakers need all kinds of tools in their tool chests.  One use is getting some Must temps up another getting rid of stinkies.

So back to the story of these two yeasts.  Can you believe the Yeast Charts when they say a yeast has moderate fermentation speed?  I don’t think so. In fact I think the following will be quite illuminating.

We start with a cooler winery in this case in the 60s.   Again the grapes arrive on Day 1 at 48

Degrees.  The Vats are wrapped with insulation.   The vats consist of 2  ½ ton Cab Sav (28 boxes each)  1200 Pounds of Petite Verdot, and 648 Pounds of Barbera.  All vats recorded 27 Brix.  Initial PH for the Cab was 3.58, and 3.71 for the PV.  The Barbera was 3.3. All vats were watered back to 25.5 Brix.  The tartaric was added, at the rate of 6 grams per litre to make up for the water addition to the Cab and PV. No acid was added with the water addition for the Barbera   The yeast for the Barbera is BM 4×4  all the others get BDX.   With the vats now unwrapped on day 3 the temps of all the vats are 63 degrees.  The yeast cultures are pitched.  On day 4 we are at 22 on the Cab and PV at 74 degrees and  18 on the Barbera.

As for the Nutrient Story all vats received Fermaid O as the Cap was forming,  Fermaid K when the Cap was established , another dose of Fermaid K at 18 Brix and a dose of Fermaid O at 12 Brix.  Now it starts to get interesting.  On Day 6 the Barbera is at 10, while the Cab and PV are at 18.  Yet the temps are 73.  Where is the heat?  I wrap the vats again to keep the heat in hoping it will rise.  It is cool in the winery.  On day 8 the Cab is at 10 and we reach 80 degrees but the Barbera is now at 1 at 77 degrees.   So much for Moderate Speed for BM 4×4.  On day 10 we reach 4 with the Cab and PV while maintaining 80 on the vats.  The Barbera is now minus ½ and on day 11 it goes to minus ¾ where it remains until pressing.  The Cab and PV continues to divide by half each day and gets to minus ½ on day 14.   Mission accomplished.

What conclusions can you draw?  For me I think with Temp the same, Brix the same to call both yeasts moderate is wrong.  Not getting higher than 80 even while the Brix dropped super quickly in the Barbera is a bit odd.  What would I do different.  Not much except with a cool winery and wanting to reach 85 degrees I think a small dose of DAP at 18 brix would have helped me get there.  Let the DAP Trolls panic.

More reading for DAP Trolls  here ….goes back to 2010 but still worth a read or a laugh…http://www.westchesterwinemakers.com/2010/10/12/dap-fear-syndrome-oh-no-what-can-we-do/

 

12 Responses leave one →
  1. Proud Puppy permalink
    October 17, 2016

    DAP works great for putting the kabosh on the stinky H2S problem, and halts it immediately. I have found though that the ramp up that happens causes a rebound of H2S often and they return 12-24 hours later. I have managed to avoid this by baby feeding and giving a little every hour or two, and spreading the dose out over the course of a day or two, (obviously not while I am getting any sleep!). Not easy to do if you are dealing with several tons, but fwiw it works on 1-2hundred pounds like a charm. Fermaid-O is also very effective and keeps the H2S down without a ramp up of temp and I have been using it for a couple of years.
    I do use full whole berry ferments and that has really helped keep the kinetics more steady, and am still able to get mid 80’s for a day or two without even insulating a small Brute.

  2. Bzac permalink
    October 20, 2016

    My standard protocol has changed a bit .
    I’m firmly on the no Dap side .
    Why ? It either works or causes more problems .
    It can actually make h2s worse , cause runaway kinetics etc .

    And bottom line. It doesn’t make the wine taste any better .

    I do use some fermaid K , which has some dap in it .

    So my protocol looks like this

    Hydrate with go ferm and pitch the yeast .
    At the end of lag phase I add I gram per gallon fermaid O .
    This organic nutrient is much easier for the yeast to metabolise , especially early in the yeasts life cycle . At this early stage inorganic nitrogen is hard to metabolise and can actually present some toxicity to yeast early in its life cycle .
    Fermaid O gets the yeast off to a nice gentle start . You get a gentler arc of a fermentation curve rather than a jack rabbit start with a quick heat peak .
    Then at 1/3 or the way into the ferment I add 1/2 gram per gallon fermaid K .
    Fermaid k contains more YAN and at this time the yeast gets it when it’s most active , the population is at its largest and it’s nitrogen demands are greatest .
    Now if I think the must is low in YAN , i.e. It’s over or under ripe or I simply don’t know the grapes ( never worked with the source) , I use 1 gram per gallon fermaid K for this second addition . So if in doubt , I use a full gram .

    Now , historically if I picked up a whiff of h2s between 1/3 and 1/2 dry , I would add some dap.
    Which as I said either works or makes it worse .

    After going to a lallemand lecture on nutrients , and likening what I found in their research , I understand that when yeast are stressed , they react better to organic nitrogen than inorganic . So my rescue nutrient is fermaid O , not dap .

    So I took all my old dap supplies , mixed it with water and poured it on my tomatoe beds .
    My beefsteaks loved it .

    So going forward I see no need to have dap on hand .

    I should also say that I’m a minority owner or Renaissance yeasts , a Vancouver company , we make wine and beer yeasts that simply cannot produce h2s .
    If you have h2s issues every year or are working with Chilean or late sprayed fruit . Try these out and combine them with my recommended nutrient protocol .

  3. Bzac permalink
    October 20, 2016

    If I was a ” organic only” nutrient disciple , I’d definitely only use the Renaissance yeasts for the safety net they offer against h2s development .

  4. Gene Fiorot permalink*
    October 20, 2016

    Good Info Zac !

  5. crazy run ranch permalink
    October 21, 2016

    Hey Gene, I was starting to think you had drowned in a fermentor or something, glad to see you posting heavily opinionated discussions once again. I’m with you on some things here but not others. First the yeasts. The charts were established based on controlled conditions in a lab. They are guidelines and IMO, should only be used to compare rates on the same grape. Barbera in limited experience, loves to ferment and does so quickly. Pinot Noir often likes to rip through as well. I would still rate BDX and BM4x4 as moderate fermentors but consider there are other factors that make things happen faster or slower. As for heating up a ferment using DAP, yah that might work. But it does by speeding up fermentation which means shorter, in conflict with your goal. If your yeast is stressed by something other than nitrogen difficiency, adding DAP is just going to speed up the yeast multiplying and create more H2S as Zac mentioned. If your issue is purely nitrogen, then yes, it can be perceived as a magic bullet. We toolbox contains no DAP, Ferm K has it and it is more versatile so why bother? While we are talking stinkies and H2S, consider that amateurs seem to have more issues than pros. Do you think that this is because they throw products at their problems? I can tell you that’s not the case. First, I think many freak out over a little H2S, dump in the magic dust and proclaim it cured. How do they know that your yeast were just showing some stress that didn’t pass anyway? Another approach would be to note that one fermentor smells off and to pay attention. If it gets worse, then take action but probably just aeration. If it continues worse, consider nutrients, temperature, massive aeration, etc. But most pros don’t immediately reach for the DAP. I find that some H2S is generated in most ferments and it almost always is a non-issue. The last time I had a major problem, it was a vineyard with ongoing issues each year despite heroic efforts to address it. I finally got a clean fermentation from it by bitching at the vineyard manager for spraying sulfur after veraison. Problem suddenly went away. If you suspect your H2S issues are coming from your one and only fruit source, I would go with Zac’s super non-farting yeast.
    As for lengthening fermentation/skin time and also getting some decent heat, I say this makes for better wine everything else being equal. As I said, using more nutrient can have a reverse effect. How about innoculating with less yeast? Less nutrient (OMG, did I just write that?) Or using your wild yeast? More whole berries. Let it get lower before pressing. Covering and let it sit on the skins for an additional day. Its all open for considering, just don’t let your pre-determined goals get in the way of what’s happening before your eyes, ears, and nose.

  6. Gene Fiorot permalink*
    October 22, 2016

    Hey Steve ! Well you make some very good points for discussion and thought. Lots of good ideas to lengthen the time frame. As for H2S it is not really a problem with Lanza/Musto Grapes but this year a member thinks he detects some in his Petite Sirah. I think he is over reacting.

    But what has me very interested is your comment regarding grape variety making a difference in fermentation time. Let’s assume crushed berrie, brix and all the rest being the same. What is it about a grape varietal which will ferment slower or faster? I cannot see any reason for that yet it appears to happen.

    Oh and as for heavily opinionated posts, truthfully I have been running out of controversy lately. LOL

  7. Bzac permalink
    October 23, 2016

    I must admit , I haven’t had h2s in a very long time . Even without the Rennaisance yeasts .
    And of all the h2s ferments I get asked about , 90% of the time I ask what nutrient did you use .
    It’s usually none , or DAP only .
    Or they used fucking Montrachet with none or dap.

  8. Gene Fiorot permalink*
    October 25, 2016

    I think you need to explore with the Musto Wine Grape Company using your yeast. After all they are the leading suppliers of Chilean Grapes. For sure there is no secret of H2s issues with those grapes.

  9. crazy run ranch permalink
    October 28, 2016

    Of course I’m happy to see a heavily opinionated post Gene. It seems this season has been short on spirited arguments.
    I cant tell you why some varietals like to ferment faster only that I’ve seen it and I believe it. This year I made some Merlot and Cab for a client using BDX for both. The Merlot came first and we had two fermenters of the same fruit. I was surprised at nearly exact kinetics between the two. Not all yeast do that, BDX definitely is a dominant yeast. My Rhones ferments tend to vary more even when innoculated. How is everyone’s view of 2016? Super quality to my eyes. Great chemistry and really fragrant wines. Can’t wait to finish MLF and see what they really taste like.

  10. Gene Fiorot permalink*
    October 28, 2016

    I wish someone could shed light on this mystery. It is baffling. as for 2016 It is going to be an amazing vintage. Everything seemed to be in order. Nice Skins, Numbers really nice and a long hang time compared to the last 2 years. I agree Super Quality.

  11. Proud Puppy permalink
    October 28, 2016

    Just noticed the above comment on the Petite Sirah. Agree this year a slight whiff appeared midway, but nothing I would call a real issue, and it was right before the Fermaid-O and lasted until the last 5 Brix, Lessened a little after Fermaid-O . But it was handled with a little elbow grease in the punch downs, with some venting aeration. Not detectable at all in the post ferment. The Washington State Merlot is another example of the quality of this year. Phenomenal fruit for 2016. Fruit this year had a little dehydration due to hang time, but adding non-acidulated water of about 6-8 % brought the Brix to 25 to 26 range and pH was still on target at 3.6 +/- and this put fruit back to natural state. Atlas Peak that is a real stunner. I really had to. Really had to!

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