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  • #16
    Thanks

    Originally posted by UnFermentable View Post
    My suggestion would be to plate samples from the heat exchanger before going through a complete breakdown. I have seen many people have issues with breaking down heat exchangers. Usually you would want to install a new set of gaskets. You also have to make sure that you torque to proper specs, in proper sequence, and that you pay close attention to the pack depth. You should check flow rates before and after.

    I would opt to CIP it in reverse with strong caustic (or PBW), flow in reverse should be like 50% more than your forward usage (150% of operating flow). You can also pulse the flow if you have a valve on the exit side of the HX. Personally, I also like to pack my heat exchanger with PAA between brews. PAA will kill most all organisms (that we typically worry about) after 6 hours, even at an extremely low concentration (5-10 ppm). If you have a braised copper exchanger, then you want to be very careful of any acids you run through. Nitric is very reactive with copper in particular. Thermaline and Alfa Laval both make great exchangers, but you should be able to make good beers with a simple braised copper exchanger if your process is solid. I have used them on pilot systems for many years without issue.

    Usually Lactobacillus will drop your gravity to below 1.010, but it may not in all cases. pH would be another good measurement tool in these cases, but lab information will help as well. Total acidity would be the best measutrement, but few do this process. You can ask whomever does your lab process if they can measure the pH of the sample. Your fermentation temps should not be a major factor if it is in fact lactobacillus. Then it comes down to CIP.

    While malted barley is the primary source of lactobacillus in the brewery, a solid CIP/SIP process should virtually eliminate all the vectors for contamination. Think through every step of the process and find where your highest risk is. Usually this is upon pitching (or propping) yeast for most people. Do you open the fermentor to pitch yeast? Do you pitch in line? Do you propagate your yeast? Do you sanitize the outside of your yeast container? Is your yeast clean? Everyone assumes that an initial pitch from a reputable manufacturer is clean, but you can ask Left Hand brewery about that. Has every surface of your fermentor had adequate time contact with your sanitizing solution? Foam can inhibit contact with surface.
    Thank you. Lots to consider here. Will be getting to work on our HX tomorrow. Getting some lab work done soon as well. We do pitch our yeast (dried yeast that has been hydrated) through the top of the conicals. We try to limit exposure to air, but there is some. The yeast container is sterilized--front and back. It is new yeast, and I assume it is good (US-05), but will certainly consider testing it (or buying a new supply).

    Thanks again,
    Tim

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    • #17
      You let it air dry? You should clean your tanks with caustic or pbw, though you will learn to love caustic when you realize how long pbw takes compared to caustic, then let them dry open. On brew day, rinse with water and sanitize, do not open your tank again from this point forward until you are cleaning it after the brew. I would also recommend getting away from StarSan and using peracetic acid, it is more quickly effective against most things and it is non foaming. If you really want to chase down where the issue is, you need to plate samples of wort at all places, so get a sample leaving the HX, get a sample entering the FV, get a sample from in the FV but before you pitch yeast. Then get another sample at the end of fermentation to see what is there. Each plate will tell you if the beer is clean at that point or not. Big areas of contamination that are possible are in your hoses and hx. I do think that it is odd you are getting lacto flavors at normal ferm temps, lacto is pretty slow at those temps, and yeast should out compete lacto, along with anything 20 IBU or higher will pretty much inhibit lacto. US-05 has been known to have acetaldehyde and also strong pear esters that are sometimes confused with acetaldehyde. You should send a sample of beer to a lab for testing, they can tell you if it is acetaldehde or not, along with lots of other good to know things. You can try lowering fermentation temperatures if it is just an ester issue.

      Originally posted by thilton View Post
      Thank your for our response.

      Our cleaning process--for kettles, conicals, and brite tanks--involves scrubbing everything with a caustic solution (1 tablespoon of PBW powder per 5 g of water) rinsing everything thoroughly with hot water and then showering all surfaces with a StarSan solution. I believe that is one ounce of StarSan per 5 g of water. We let that air dry without wiping. We do the same for all hoses (running successive solutions through them) and all valves and fittings as well. We had been cleaning and sanitizing the night before brewing and then quickly sanitizing the conicals again the morning of brew day. Then we began doing it all the morning of the brew to better ensure everything was clean and sanitized.

      As for yeast, we're using a dry yeast, SafAle US-05. Pitching 80g per barrel. (We use 1, 2 and 3 bbl conicals.)

      Good idea about making sure all conicals are sealed when milling. I believe they are, but I will be sure to check that.

      As for temperature control, the fermentation room is set for 67 F and remains within 3 degrees of that at all times. We have a small controller hooked up to a small heater and an air conditioning unit. The thermometer on the conicals has reached as high as 72F during active fermentation and as low as 65F afterwards.

      Beer is finishing at expected gravity, between 1.010 and 1.015 for our recipes.

      We'll keep working on our sanitation and temperature control as well as limiting air exposure during transfer to conicals.

      Thanks again for your suggestions.

      Cheers,

      Tim

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      • #18
        Thanks, Everyone!

        Much thanks to all who responded to this thread. We took your advice very seriously and it seems to have worked out quite well. Lab tests confirmed we had a lactobacillus problem. We looked closely at our processes and equipment and made several changes. We moved all of our grain crushing further away from our brewing and fermentation areas--in a separate space behind closed doors. We've also been more careful about making sure our conicals/fermenters are covered (and behind closed doors) during our mash-ins. We've also done a better job cleaning our plate chiller (both after and before brewing)--flushing it backwards and forwards with water, a non-caustic cleaning solution and water again. We also began cycling hot wort through it on brew day before starting the cold water/heat exchange for a quick sterilization.

        We also cleaned the entire brewery from top to bottom, getting rid of any remaining grain dust (which really was just about everywhere). Finally, we upgraded our cleaning solution and liquid sanitizer as well. We can't be sure which of these changes made the difference, but our last 3 beers are infection free. We decided that it really doesn't matter what the problem was because it is gone now and the changes we've made are good SOPs for any brewery. Onwards and upwards.

        Thanks again everyone.

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