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Thread: Lactose in a high plato wort and low dissolved oxygen issues pre-fermentation

  1. #1
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    Lactose in a high plato wort and low dissolved oxygen issues pre-fermentation

    Our milk shake style double NEIPA has a lot of sugar in it, as a result I'm having problems with to little dissolved oxygen before pitching yeast.

    Key factors in our process:

    - Lactose is added to a 16° plato wort at fifteen minutes until flame out to bring the final plato to 18°.

    - We knockout after whirlpool hop additions at colder temperatures via a stainless coil submerged in cold water to avoid clogging our counterflow heat exchanger. So, when the wort is in the fermenter it is about 110 to 130 degrees Fahrenheit.

    - After chiling the wort to roughly 65°F, we dump the trub and oxygenate via pico stone attached to the side of the fermenter before measuring DO and pitching yeast.

    - We do not have brite tanks. We just ferment, drain trub and carbonate before kegging.

    This process usually works but with the addition of lactose the wort is too thick with sugar to dissolve oxygen. Our DO meter is not in question and is working correctly but we get readings below 2ppm after multiple attempts with different port locations for the pico stone for adding o2. Low o2 means a stressed yeast which constantly gives us the same phenolic off flavor. (CIP SOPs are not in question as there is not an infection in this case; we did not get acetic acid or funk or lower pH. Chlorine and chlorine levels not in question either.)

    In what way can I add at least 15ppm of o2 to this high sugar beer? I'd in line o2 during BK to fermenter transfer out of the question because of the high temperature of the wort? Can I add lactose without oxidizing a fermented beer to the fermenter prior to packaging?

  2. #2
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    According to one calculator I have, you can only dissolve about 15 ppm oxygen at these gravities if you use both pure oxygen and have a constant atmosphere of pure oxygen (though to be fair, this calculator is primarily for gas injection into flowing liquid).

    So I suggest if you are not able to in-line oxygenate with suitable kit to guarantee total solution of the oxygen, the best option is to aerate / oxygenate after yeast pitching. However, when I used to brew barley wines, the aeration rates were well established by trial and error, and then well documented - so an occasional brew at this gravity may not allow you to establish a consistent procedure.

    If you are going to do this regularly, get yourself some proper injection kit with flow control and back pressure on the cold wort, with long dissolving times circa 30 seconds plus.
    dick

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    Does your whirlpool completely fail for this beer? A quick google finds inline triclamp stainers can be had for around $150, which doesn't sound like a crazy investment to keep that chiller safe from the occasional stray hop particle on every brew, although this probably won't cut it if you've got so many hops your kettle's side outlet is completely buried when you brew this beer. (I'd point you towards the one we use where I work, but I'm pretty sure it's something our welder fabricated from parts) Then you can inline oxygenate at will.

  4. #4
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    Quote Originally Posted by dick murton View Post
    According to one calculator I have, you can only dissolve about 15 ppm oxygen at these gravities if you use both pure oxygen and have a constant atmosphere of pure oxygen (though to be fair, this calculator is primarily for gas injection into flowing liquid).

    So I suggest if you are not able to in-line oxygenate with suitable kit to guarantee total solution of the oxygen, the best option is to aerate / oxygenate after yeast pitching. However, when I used to brew barley wines, the aeration rates were well established by trial and error, and then well documented - so an occasional brew at this gravity may not allow you to establish a consistent procedure.

    If you are going to do this regularly, get yourself some proper injection kit with flow control and back pressure on the cold wort, with long dissolving times circa 30 seconds plus.
    Thank you for your reply.

    We do use food grade o2 with a pico stone in line with more standard beer styles. That method is well established. This style in particular is in question because we've been able to oxygenate NEIPAs without lactose via the pico stone installed on to the side port of the fermenter; this method is also established. For whatever reason, this style did not take to o2 well, if at all.

    We're going to try to create our own o2 solubility curve with different sugars (maltose, dextrose/maltose , lactose/maltose) to hopefully give us some answers.

    Any other insights are appreciated.

  5. #5
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    Quote Originally Posted by feinbera View Post
    Does your whirlpool completely fail for this beer? A quick google finds inline triclamp stainers can be had for around $150, which doesn't sound like a crazy investment to keep that chiller safe from the occasional stray hop particle on every brew, although this probably won't cut it if you've got so many hops your kettle's side outlet is completely buried when you brew this beer. (I'd point you towards the one we use where I work, but I'm pretty sure it's something our welder fabricated from parts) Then you can inline oxygenate at will.
    Thank you for your reply.

    We use those strainers for less hoppy beers coupled with an inline pico stone and food grade o2 for every other beer style. This submersion chiller to fermenter method is a direct result of clogging those strainers multiple times during knockout. After fully pumping out, we chill the beer and drain trub before oxygenation and pitching. This always works for NEIPAs without lactose.

  6. #6
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    We've established inline oxygenation methods for milkstouts and a 28.3 plato stout (a lactose beer and a very thick and sugary beer) that only differ in injection time and amount (L/min via flowmeter). This NEIPA with lactose is standing out.

    FWIW, we've had to dump two other NEIPAs due to the same phenolic off flavor (same yeast strain but we attributed the phenols to longer cold storage time after purchase, which creates a stressed, less viable yeast[?]). The o2 ppm were above 15 for those dumped.

    Our water is treated with two carbon filters and a half campden tablet per strike and one half for sparge waters. (Maybe this isn't enough to scrub chlorine/chloramine from our water?)

  7. #7
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    You don't say what you brew volume is, so simply stating half a campden tablet per tank isn't a lot of use. But it does sound low. Unfortunately how much you need to add does of course depend on water volumes and chlorine content. Your supplier should be able to help out with calculating how much to add. In my experience, a little too much SO2 is not harmful to the beer.
    dick

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    Quote Originally Posted by dick murton View Post
    You don't say what you brew volume is, so simply stating half a campden tablet per tank isn't a lot of use. But it does sound low. Unfortunately how much you need to add does of course depend on water volumes and chlorine content. Your supplier should be able to help out with calculating how much to add. In my experience, a little too much SO2 is not harmful to the beer.
    Wow I can't believe I didn't mention that! Our brewpub/pilot system is 3.5 BBLs. A half campden tablet is treating a full HLT at 120 gallons.

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    Of course your campden tablets may be a different size to the following - so you could adjust.

    Checked with Murphy & Sons - 1.75 grams per tablet with approx. 60% effective SO2 content. One tablet will normally treat 1400 litres water. One of the local breweries runs at about double this rate will no apparent ill effects. So your addition rate looks to be fine, with the proviso that the tablet sizes are the same!!

    I have to say I was surprised how little needed adding, hence my earlier comments.
    dick

  10. #10
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    Quote Originally Posted by dick murton View Post
    Of course your campden tablets may be a different size to the following - so you could adjust.

    Checked with Murphy & Sons - 1.75 grams per tablet with approx. 60% effective SO2 content. One tablet will normally treat 1400 litres water. One of the local breweries runs at about double this rate will no apparent ill effects. So your addition rate looks to be fine, with the proviso that the tablet sizes are the same!!

    I have to say I was surprised how little needed adding, hence my earlier comments.

    We use BSG campden tablets, according to their website they are;
    "...tablets made with Potassium Metabisulfite. 1 tablet per gallon equals 30 ppm free SO2. Each tablet is about 0.5 g.".

    Does our rate of ~0.25g per 105 gallons (not 120 gallons, my error) still look to be okay to remove CL from our water?

    What is the relationship between SO2 and CL and how does less SO2 equal less CL?

    Our average amount of CL in our water is 41.5 ppm.
    As for SO4-S the average is 18.5 ppm.

  11. #11
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    So the Murphys tablets are recommended at 1 tablet (1.75 grams) per 1400 litres which gives an SO2 content of 0.785ppm

    BSG tablets - 0.5 gram gives 30 ppm in 3.78 litres

    So if my brain isn't too befuddled, this means to achieve about the same ppm as Murphys recommend, you need to add three tablets per 105 gallons (397 litres)

    The local brewery work on about double that with no adverse effects, so because your water may have a slightly different chlorine content, I think you could add up to six tablets quite safely. Try 3 and see if that makes any difference. If you still have chlorophenolic taints, up the dosage.

    It also sounds as though you should be changing your carbon filters more regularly. There should be an advisory note saying how much water each cartridge (I am assuming you are using cartridge filters) will treat.
    dick

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