Help with some math, and a question...

Discussion in 'Homebrewing' started by Lukass, Jul 3, 2018.

  1. Lukass

    Lukass Savant (936) Dec 16, 2012 Ohio

    I need some help figuring out what my OG is gonna be on a saison/wine hybrid that I’ll be brewing this coming weekend.

    I suck at math, so I’d love it if someone could take a stab at figuring this out for me. Here are the specifics:

    1. I am using 1 L of white grape concentrate, that when mixed with 3.2 L of water, has a gravity of anywhere from 1.082-1.092. I plan on using it as is, and not mixing it with water.

    2. The target OG for the saison wort will be around 1.053 post-boil, and I plan on having around 5.5 gal into the fermenter.

    Any idea what the combined OG would be if I mixed this white grape concentrate with my chilled saison wort before fermentation? And, is this a good idea to do, or should I add the grape juice to the saison as fermentation begins to slow (Like I would with a sugar addition)? I really don’t want to do a secondary on this one, hence my questions about using the juice in primary. Thanks in advance.
     
  2. VikeMan

    VikeMan Meyvn (1,470) Jul 12, 2009 Pennsylvania

    Let's say the water/grape mix comes in at 1.087, then:

    ((1.087 - 1) x 1.10952) + ((1.053 - 1) x 5.5)
    ---------------------------------------------------------- +1 = 1.059
    1.10952 + 5.5

    In a hurry. Someone can correct my math if needed. Brewpub calling.
     
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  3. NeroFiddled

    NeroFiddled Poo-Bah (10,359) Jul 8, 2002 Pennsylvania
    Premium Trader

    @VikeMan seems to have the numbers down. Looks right to me. As for adding it prior to fermentation starting or later on I would suggest going later on, once fermentation starts to slow a bit but certainly before it stops.
     
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  4. KeyWestGator

    KeyWestGator Devotee (492) Jan 21, 2013 Florida
    Trader

    In his hurry, I think Vike missed that you were not going to dilute the concentrate. I just tried to fix it and came up with an obviously wrong answer. And I too am running to begin the festivities, so will tag somebody else in!
     
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  5. Lukass

    Lukass Savant (936) Dec 16, 2012 Ohio

    You guys are awesome, thanks. @VikeMan and @KeyWestGator yea, I was not planning on diluting the concentrate with water, so would probably be a much higher og for the juice, but also at a less amount. I would guess that the og you calculated (1.059) shouldn’t move too much if I diluted or didn’t dilute the concentrate though, right? Since it’s the same amount of sugars being added either way.
     
  6. Push_the_limits

    Push_the_limits Initiate (30) Feb 8, 2018 Antarctica

    ((3.2 / 3.78) X .087)) / (5.5) = .0134

    1.053 + .0134 = FG = 1.066

    However, I wasn't totally sure if you will have 5.5 gal before you add the grape concentrate, or after. Since 1 L is more than a 1/4 gal, it is significant. This math assumes you have a 5.235 gal wort that would become 1.053 if you added just water up to 5.5 gal. However, you add 1L of your grape stuff to to get 5.5 gal @ 1.066.
     
    #6 Push_the_limits, Jul 3, 2018
    Last edited: Jul 3, 2018
    Lukass likes this.
  7. VikeMan

    VikeMan Meyvn (1,470) Jul 12, 2009 Pennsylvania

    Crap. Reading is FUNdamental. With undiluted grape concentrate (where 1.087 in 4.2 liters = 1.3654 in 1 liter (0.264172 gallons)...

    ((1.3654 - 1) x 0.264172) + ((1.053 - 1) x 5.5)
    ----------------------------------------------------------
    0.264172 + 5.5

    + 1 = 1.067

    ETA: This assumes 5.5 gallons of just the saison wort portion. And the grape concentrate adds 1 liter.
     
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  8. Lukass

    Lukass Savant (936) Dec 16, 2012 Ohio

    TooHopTooHandle likes this.
  9. Lukass

    Lukass Savant (936) Dec 16, 2012 Ohio

    Thanks man. I was thinking this as well, will probably add as an addition during high krausen, or as ferment begins to slow.
     
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  10. Lukass

    Lukass Savant (936) Dec 16, 2012 Ohio

  11. dmtaylor

    dmtaylor Aspirant (205) Dec 30, 2003 Wisconsin

    I would say yes I think it's okay. I'd be more concerned about sorbate.
     
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  12. VikeMan

    VikeMan Meyvn (1,470) Jul 12, 2009 Pennsylvania

    I suspect it won't hurt anything. Wine makers add K-Meta to their must to kill wild yeast before pitching their wine yeast.
     
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  13. Lukass

    Lukass Savant (936) Dec 16, 2012 Ohio

    Description says it can be added to wine to boost alcohol so I didn’t ‘think’ it’d be a problem, but this is good to know. Thanks man

    Ok, thanks. I assume it would be a problem if used in high amounts, but as a preservative for the must it’s probably not a high dosage that I’ll be adding.

    Appreciate your guys’ feedback, once again!