Grape Juice Stuck Fermentation

Sam
edited November 6 in General

So I put a 200L wash of grape juice concentrate in the fermenter and pitched it three days ago but am seeing no real activity...

I diluted the concentrate to an SG of 1.097, added about 80g of DAP and then re-hydrated 80g of EC 1118 in go ferm protect evolution and pitched.

Nothing much is happening, I can see a couple of bubbles if I stare really hard for a few minutes but the gravity hasn't moved at all.

I'm tempted to re-pitch with some more EC 1118 but I just feel there is something that I'm missing like the pH. I didn't check or adjust the pH as I never have and haven't had this problem before and whilst I haven't used EC 1118 before I ready that it is effective across a broad range of pH.

Any help or pointers is much appreciated as this is my first time fermenting fruit and using EC 1118 and I don't want it all to spoil.

Comments

  • I have done a similar brew to this and remember major ph adjustments and aeration in the start. I also used EC1118. I was after Pisco and Raki/ ouzo. The Pisco turned out good and never got around to the raki

    Will have a hunt but believe I got a lot of info from a gentleman who’s name escapes me in the raki arak thread. He had most detailed info from his runs and was from around that Lebanon area.

  • Yes check the Pisco Raki Arak thread. My initial ph was 2.8 which I had to raise quite a lot. There is a fair bit of info there.

  • Thanks, I might splash out on a pH probe tomorrow and see whats going on. Its not something I have had an issue with so far.

    Am I right in thinking you used Calcium Carbonate to raise the pH?

  • edited November 6

    Yes I did but @Grim suggested lye somewhere in that post. I remember it foamed like crazy when I used calcium carbonate but seemed to work. Just had me worried.

    I also bought a total ph wine test kit for a reason I can’t remember. That is a liquid test kit a I don’t believe a ph stick meter will be accurate ( but open to suggestions). A total titratable acid kit.

  • Ok, the pH papers I have are saying somewhere between 2-3 but I was going to get a stick meter to try and be more accurate.

    From what I can figure out I have three options to raise the pH that I can get my hands on quickly. Lye (caustic soda from Bunnings), Sodium Bicarbonate or Calcium Carbonate.

    Is there a formula anywhere to work out how much to add to correct the pH?

  • No formula, you’ll need to add a little at a time and monitor. Because pH is logarithmic, the amount you’ll need to add doesn’t increase linearly.

    Wait a few minutes each time, the pH change is not instantaneous. This is especially so when using chalk (calcium carbonate). Also, watch for foaming with sodium bicarbonate.

  • I will do it slowly then and keep an eye on it.

    Once its in the right range should I repitch the yeast or will the stuff thats in there get its act together?

  • edited November 6

    The amounts you added weren't excessive, there shouldn't be any real risk here of overpitching. So yeah, pitch, it's cheap insurance.

    You shouldn't need to go much higher than a pH of 4 or 4.5.

  • Also I can’t see anywhere on the Technical Data Sheets an optimal pH range for EC1118... what should I be shooting for?

  • edited November 6

    pH of 4-5 is considered optimal for most Sac. yeasts, however, most wine yeast are happy to go much lower than a pH of 4 - keep in mind the most white wines finish fermentation around pH 3-3.3.

  • @sam 4.5. Its not very happy over 5.5. I have used ec1118 almost exclusively. Under 5 and its happy and the yeilds are a lot better.

  • I'd be making sure there's no preservatives in the concentrate too.

    StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand

  • Thanks everyone, I found some bicarb in the cupboard last night and managed to get the pH up to about 3.5. I planned to go get more first thing this morning and finish adjusting it to just over 4.0 then repitch the yeast.

    Anyway this morning it’s bubbling away quite happily. So I’m thinking it’s probably best to leave it alone to do its thing and if it stops fermenting or slows down then check and adjust the pH then, or should I try and get it to 4.0 now so it doesn’t need adjustment later on?

  • @punkin I checked that, its a concentrate for wine making so it has a little Sulphur Dioxide in it but thats it

  • Mate. Its going to taste like shit. Everyone says the sulfur carries over.

  • Sam
    edited November 6

    I will see how it goes, I saw GD50 used the same product (albeit the Muscat variety not the Semillion/Chardonnay) and it seemed to be ok.

    I really just wanted to practice techniques etc ahead of fresh grapes becoming available in the Hunter in a few months so then I know what I'm doing and am ready!

    Fingers crossed!

  • I’ve not done a grape juice but my sugar washes with ec work with the following parameters pretty reliably.

    • SG below 1.075. Less work on yeast babies to start.
    • start ph of 5.5-6
    • first 24 hour ph will drop to 3.5-4
    • hold ph between 3.4 and 4.5 optimally. Below 3.3 and 2.7 it slows noticeably. There seems to be a happy spot for me at around 3.75-3.9.
    • goes pretty quick and stays clean (7-9 days) with temps between 25 and 29. Below and it ferments slow for me, above it creates off flavors.

    If it were me, in addition to the already suggestions from others I’d look at lowering the SG at the start. Could add more in as it progresses if you want. My first reaction after reading was “split it(water it down), adjust ph and re-pitch”

    As for ph adjustments. We use sodium hydroxide now and it’s great. Before we used baking soda which works fine until you get good enough at ferments that you KNOW (not just suspect) it’s causing issues. I will suggest keeping adjustments with baking soda in a 200l drum to 50g max. The foaming at larger doses can get out of hand and make a mess. (Guess how we figured that out)

  • Its foaming away very merrily now so I'm just going to keep an eye on it as its already foaming way more than I am used to!

    I was actually aiming for an SG of 1.075 and even used a brix dilution calculator and everything, when I checked as I was diluting it, it was coming up shy of where it should have been so I added another 10L of grape juice concentrate. At the end I was a bit befuddled why it was lower than it should be so got the mash paddle out and gave it a damn good stir, turns out my calculations were correct and the SG had gone up to 1.097...

    Anyway I thought about diluting it but figured Champagne is around that ABV so would see how it goes.

    Next time I'm going to stick to an SG of 1.075 as at that ABV 200L of wash strips down into my 50L boiler for a spirit run nicely. I'm also going to try the Sodium Hydroxide next time as well because given the adjustments required I think to much bicarb will be required.

  • So, just incase anyone in the future is in the same situation as me and is reading this thread, wondering about using Bicarb, be very very careful once it start bubbling...

    I thought as I'm going to be away for a couple of days I will raise the pH to 4.0 and thought I will put a bit more bicarb in, I put about 2 Tablespoons in and it was like putting mentos in coke. The whole thing just went nuts and foamed right out the top, lost about 20L and now have to explain to the wife why all the towels are in the washing machine and her mop smells of grape juce...

    Bottom line, once its bubbling dont add anymore Bicarb!

  • Bicarb claims another victim.

  • @grim I was so bloody careful as well, that's why it surprised the hell out of me.

    With using Sodium Hydroxide in powder form do you add it dry to the fermenter or do you make a solution with water and then add the solution?

  • PPE with caustics. Gloves, apron, goggles.

    Granules, beads, or pils are nice, because you can measure out and dose with less worry about spillage and splashing.

    I feel like it’s safer, but we are still talking about caustic. If pretzel makers can be safe, so can we.

    I stay dry, because when I make a liquid, I’m going to inevitably spill it on myself.

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