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  • Whirlpool question

    Hello All,

    I'm new to this forum and I'm amazed at the wealth of knowledge and willingness of people to offer up opinions and fact to help other brewers out.

    I just had a question about using a whirlpool to compact mash solids. I've heard several opinions about the impact of introducing too much oxygen before the boiled wort has been cooled, and I wondered

    1. what are peoples opinions about the introduction/aeration of the wort before it's cooled down after the boil?

    2. if you believe hot wort areation is a big enough factor to worry about, what process would you use instead of whirlpool to keep the solids to a minimum?

    Thanks for the feedback

    Cheers,

    Andy

  • #2
    I'm a bit confused by your question, as you refer to "mash solids". My mash solids are pretty much left behind during the vorlauf/sparge process and don't make it to the kettle at all (well, at least not very much). Are you referring to the coagulated proteinaceous trub that forms during the boil?

    Rob
    "By man's sweat and God's love, beer came into the world" -- St. Arnold of Metz

    Comment


    • #3
      oops

      Sorry,

      You're right... I mis typed. (or was, like a usually am, less than clear)

      I meant any solids or particulate that slipped by during the sparge, as well as hops, proteins etc, etc... basically anything that is bunched together by using a whirlpool after the boil.

      so actual solid matter aside composition... I was just wondering what your opinion might be about using a whirlpool while the wort is still hot and potential adverse effects of aerating hot wort after the boil.


      Cheers,

      Andy

      Comment


      • #4
        Well, I can't speak for the others here, but in every instance where I've brewed professionally, I whirlpool the hot wort. I've never worried about HSA, probably because the whirlpool process isn't inducing a whole lot of air/wort interface turbidity, and the ratio of the volume of hot wort to the surface area where it touches air isn't so high, as it might be in a homebrewing instance.
        Whirlpool away man!

        Rob
        "By man's sweat and God's love, beer came into the world" -- St. Arnold of Metz

        Comment


        • #5
          Hsa

          some research says HSA is a myth (Bamforth et al)...that aside, 02 doesn't much dissolve above 90C, so whirl away.....and knock out in a hurry. That way it won't matter.
          Larry Horwitz

          Comment


          • #6
            Thanks

            Hey Rob,

            Well put.. I do currently whirlpool and figured that the reason that I didn't notice any ill effects is pretty much exactly what you said... the the surface area to wort volume just isn't enough to make an impact, unlike when I do the occasional batch on my little herms system at home, along with the debate about whether or not HSA is even a problem that Larry points out.

            In any case I don't have a whole lot of people to discuss with and this was an easy one I figured I'd try out here :-) Thanks for your posts!!

            Cheers,

            Andy

            Comment


            • #7
              My opinion is that HSA is a big problem for shelf life longevity, and that it should be avoided at all reasonable costs. The issue is not how O2 dissolves into the wort, but rather how O2 reacts with wort compounds. This doesn't need to be a dissolution/bulk issue, but rather a reactive/surface issue. That being said, whirlpools don't introduce air into the wort. Whirlpool away.
              Phillip Kelm--Palau Brewing Company Manager--

              Comment


              • #8
                I´m not quite sure if I have understood you guys right. You want to areate your wort while it´s still hot ? Well you could do that but your beer gets a way darker color. And since gases dont get bound in liquids while still hot you get a less than good aeration of you wort --> therefore fermentation iss insufficient.
                A friend of mine worte an article about hot / cold trub removal maybe this could be of any help



                Hope I´ve helped you guys.

                Cheers

                Nic

                Comment


                • #9
                  hot-side and cold-side aeration

                  As was mentioned above by gitchegumee, avoiding hot-side aeration is especially important for the shelf-life of beer. That aside, your beer will taste better without it, too. Therefore, it should be avoided. The difference between hot-side and cold-side aeration is that the oxygen doesn't tend to react with other compounds in the wort as much at lower temperatures.

                  As with CO2, oxygen physically dissolves better at lower temperatures BUT chemically reacts more readily with other molecules in the wort at higher temperatures. There is often confusion regarding this matter. To reduce giving oxygen the needed energy to react, lower the temperature as much as the yeast can stand and do not use pure oxygen to aerate your wort. It is almost impossible to over-aerate with air, but quite easy with pure oxygen.

                  Currently, research is being done at a few larger breweries regarding this topic. Their findings are that it is possible to aerate the yeast slurry from the propagator instead of the wort or to pitch the yeast at 60 million cells per ml, both of which increases the life of the beer by keeping the natural anti-oxidants in the wort.

                  Some larger breweries also have a heat exchanger between the brew kettle and the whirlpool, which lowers the temperature to about 80 or 85 degrees C to avoid hot-side aeration. Hop additions in the whirlpool at that temperature also result in less isomerization and the retention of hop oils important for aroma, which is of course desired in whirlpool additions.

                  Comment


                  • #10
                    In addition to the comment by crassbrauer:

                    Wort precooling <90C before the whirlpool will also aid in low DMS formation during whirlpool stands.
                    Mike Jordan
                    Brewmaster
                    Boxing Cat Brewery
                    Shanghai, P.R. China
                    michael@boxingcatbrewery.com

                    Comment


                    • #11
                      DMS-P to DMS

                      Yes, as a matter of fact, avoiding DMS formation was the primary motivation for first placing heat exchangers in that spot of the brewhouse, although other benefits have presented themselves, as well.
                      Last edited by crassbrauer; 03-08-2006, 04:02 AM.

                      Comment


                      • #12
                        DMS reduction

                        interesting notes on DMS reduction....

                        I was looking for a way to reduce my knockout length in the summer months to limit the DMS I have noted in my lighter lagers (I only have a single stage heat exchanger and am limited by my municiple water temp).

                        My Idea was to run over at 80f and allow my FV to bring it down to fermentation temps.

                        I posed the question to a friend of mine Steve Alexander (HBD contributor)
                        and he replied with the following. Some is more info that I needed to know, but it does cooralate to what Mike says about getting the temp down initially to under 195F.

                        Heres my question and his reply for those interested:


                        I need your expertise on a question......

                        At what temp ( post boil) does SMM and DMSO stop forming DMS?

                        I've detected a bit of DMS in my lighter beers during the summer and
                        wanted to speed my cooling by running over at a higher temp and
                        allowing my fermenters glycol to bring it down to fermentation temp.

                        Currently we cool with city water (72 F in the summer) wich can chill
                        the wort down to within two degrees, but takes 2 hours to do so. I was wondering if I could run over at say, 85F, tat would almost cut
                        my runover in half, more like it is in the winter.

                        Thanks for you knowledge



                        Hi Jack,

                        You ask a hard question so I went back and re-read all the basic
                        sources.

                        OK the parts I remember and you probably already know already are these
                        -
                        The main players in the story are
                        SMM - S-methylmethionine
                        DMS - dimethylsulfide
                        DMSO - dimethylsulfoxide

                        SMM the original source of the others. SMM breaks down into DMS at
                        higher temperatures, and DMS can be oxidized into DMSO in the presence
                        of any number of oxidizing agents, even air. The DMSO is stable, but
                        can be converted into DMS under the right circumstances.

                        DMS is the flavor-active player here with a threshold of only 30 parts
                        per billion. DMSO and SMM aren't very flavorful, so the amount of DMS
                        in
                        the glass is the only concern. The only reason to consider DMSO and
                        SMM is that each can be converted to DMS.

                        Of course bacterial infection can produce massive amounts of DMS, but I
                        assume that's not the problem. These bacteria also have a
                        methionine/protein metabolism which can cast out DMS.

                        ===
                        SMM:
                        S-Methylmethionine (SMM) is the source of all the others. Raw grain
                        only has a little SMM, but a lot is produced as part of the
                        methionine/amino/protein metabolism of growing barley and other
                        grasses. The SMM is primarily formed in the malting process as the
                        grains germinate. SMM is probably very water soluble, but it's also
                        trapped in the interior of the barley cells. A lot of the SMM in
                        barley/malt, perhaps half, is washed out of the grain during the
                        initial
                        stages of malt chitting. About one fourth of the original amount is
                        left in the grist after mashing and the other ~one-fourth ends up in
                        the
                        wort. The yeast actually consume a fraction of the SMM during
                        fermentation to build proteins. This brings up a good point, some
                        malts, the lower nitrogen, lower protein ones, have less SMM. It is
                        claimed that pale-ale malts have the least and 6-row malts have roughly
                        twice as much SMM.

                        DMS:
                        DMS is volatile. The boiling point of pure DMS is 37C/99F, so most of
                        it boils off in the boiler. The CO2 released during fermentation also
                        blows off a significant fraction of the DMS, but it leaves the DMSO and
                        SMM untouched. Here is a weird one - DMS is NOT soluble in water, so
                        it probably floats around in the wort just like the tiny amounts of
                        oils. DMS is soluble in alcohol, so it's won't float to the top like
                        an oil slick after the ferment. Also the amount is tiny - your 20bbl
                        capacity will only contain a fraction of one gram of DMS in a very DMS
                        flavored batch.

                        DMSO:
                        DMSO is weird stuff. It's a solvent, can be used as paint stripper,
                        yet it is not particularly toxic and even has some medical uses. It is
                        NOT volatile and won't boil off (boiling point of 189C/372F, freezes as
                        18.5C/65F). It's soluble in almost everything. It's also rather
                        stable chemically.

                        SMM->DMS:
                        The SMM is pretty stable and it requires a relatively high temp to get
                        a
                        significant rate of conversion SMM -> DMS. During malt kilning some
                        fraction of the SMM is converted into DMS, but less than you might
                        expect, about half. It is claimed by several sources that about half
                        the available SMM is converted to DMS per hour at the
                        boil(100C/212F). OTOH M&BS states that at infusion mash temperatures
                        (say under 70C/158F) that only a tiny fraction (assume a few percent)
                        of
                        the SMM is converted per hour. This probably explains why lagers have
                        more DMS than ales - the decoction of the entire grist and therefore
                        all
                        the SMM creates a lot more DMS. In an infusion mash the grist probably
                        retains a lot more SMM than the grist from a decoction too.


                        DMS->DMSO:
                        This is an oxidation reaction that can happen when malt
                        degrades(stale),
                        or from oxidation of the DMS in the mash. Any DMSO formed will
                        survive
                        the boil and may be converted back into DMS by the yeast.

                        DMSO -> DMS:
                        DMSO can be converted into DMS, but this requires energy and a
                        reduction
                        process. Chemically you could accomplish this by adding some draino
                        (or any strong base) and holding it in a hot oven overnight. The other
                        means is to put it in a fermenter during the active fermentation. The
                        yeast need to chemically reduce their environments when they are
                        anaerobic so they reduce anything laying around, including a good
                        fraction of the DMSO. This chemical reduction of DMSO into DMS stops
                        when the yeast are separated from the beer. The extent of DMSO -> DMS
                        conversion is dependent on the yeast.

                        ============
                        So back to SMM -> DMS:

                        You can't really pick a critical temperature and say "below this is
                        OK". You have to consider the temperature and the time spent at that
                        temperature. At boiling there is little worry since the DMS is
                        immediately lost to the atmosphere. Once boiling stops, the DMS
                        accumulates in the wort. Here
                        is the best source of hard numbers on the kinetics of SMM->DMS
                        conversion I've found.
                        Latest news coverage, email, free stock quotes, live scores and video are just the beginning. Discover more every day at Yahoo!

                        See figures 3, 4 & 5. These guys are studying the same reaction at the
                        same pH - but in peppers, not wort.

                        So at 70C/158F, the *rate* of DMS formation is about 230 times less
                        than
                        at boiling.
                        At 86F/30C the rate is 3300 times lower than at boiling
                        At 68F/20C the rate is 14800 times lower then boiling, and abt 4.5 time
                        less than at 86F/30C.
                        This is a reasonable extrapolation form the 70C-110C data.

                        The biggest gains by far are always from reducing the time at highest
                        temps. One extra minute at 200F is worth an extra day at 85F !!
                        (give or take a factor of two). I strongly believe that the problem
                        is
                        NOT the extra time once you get the wort down to 85F, but the extra
                        time it took to get the wort from 212F down to 175F.

                        I think there are two ways to approach this.
                        1/ Boil longer and convert more of the SMM->DMS and boil it off. An
                        extra 20 min should make a significant impact - 25% - 50% reduction.
                        2/ Find a way to drop the boiling wort temp FAST. Perhaps introduce a
                        bolus of 10% pre-boiled & chilled water to the boiler (if possible).
                        The problem is due to the extra minutes spent at the highest temps.
                        Literally 1 minute at boiling produces as much DMS as one hour at 142F
                        !! If you could find a way to instantly drop the boiling wort to
                        90C/194F, then continue chilling at your normal rate you'd reduce the
                        chill-period DMS production by a factor of 4 or 5 !! That's huge.

                        Probably not what you wanted to hear but ....

                        Very interesting - thanks for the nice puzzle.
                        hope to see you at the next Saaz meeting (and yes I need to get to
                        Willoughby),
                        Steve


                        .

                        Comment


                        • #13
                          avoiding DMS

                          The reply you received was very informative.

                          Basically, you have to watch out for the following:

                          1. DMS-P (SMM) in your malt should be below 5 – 7 ppm (mg/kg). If it’s too high in your malt you can’t do much in the brewhouse to correct it. Winter barley is worse than summer barley and six-row is worse than two-row, due to their higher protein levels (Methionine is an amino acid). Over-modified barley is a problem, because the higher the FAN, the higher the DMS-P

                          2. Wort boiling: temperature, time (boil longer if you’re having problems), convection (you need a kicking boil), wort pH (more below), amount of evaporation

                          3. Whirlpool: temperature, time (just enough to let the "dust" settle before the spin)

                          I’ve read from several sources that DMSO can really only be turned into DMS enzymatically, i.e. through microbial activity.

                          As stated in the reply above, DMS formation from DMS-P pretty sharply falls off as the temperature drops, so your wort chiller, although lacking, isn’t to blame. Just drop the temperature ASAP.

                          Wort pH is important. If you leave the pH at around 5.5 to 5.6 during the boil and acidify at the end, not only will more DMS-P be broken down and driven out, but your hop utilization will be better. Acidify your wort to 5.1 to 5.2 only in the last 10 minutes of the boil.

                          Comment


                          • #14
                            Again I have a sort of informative Termpaper regarding production and reduction of DMS. A few flaws are in it (withering and klining is not so good discussed in this paper) but it should give a good overview.




                            [EDIT] Please let me know if you liked this termpaper. (Mainly beacause I have written it )

                            Comment


                            • #15
                              What if you stored the city water in cheap plastic tank and chilled it with refrigeration or even with ice, pumping it thru the HX to firstly reduce the DMS, secodly to go home earlier?

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