I looking for some ideas on storing yeast between batches. I'm currently storing yeast in the cone of my fementers and simply transfering yeast from cone to cone, just guessing on the amount of yeast that gets transfered(I haven't had any problems with doing this). I just read David Sohigian's paper "Practical Yeast Managemnet in the Brewpub" on the ABG's website and he talked about modifing a corney keg with a flexible 1/2 line down through the lid with a valve on top. Has any one used this? I have used the modified sankey kegs and they work good for large batches, but it's hard if not impossible to weigh the amount of yeast being used. I'm making 15 bbl. batches. The one thing I want to do is be able to weigh the amount of yeast I'm pitching, trying to get a little more consistancy. I don't feel safe using buckets but I will consider buckets if a couple of people out there say they've tried it with success. I think the modified corney kegs are the cleanest way to go right now, but I'd like to hear from others on this subject. Thanks, Scott
From: Scott (email@example.com)
I always tried to pitch the yeast out of a fermenter with 7-10 day old beer still on top. Less transfering mean less chance of contamination. When that wasn't possible we went to a modified Sanke keg. Stem cut out with an 8" manway on top and inch and a half fittings on the sides at top and bottom. You can weigh this on a keg scale (available through Fox for little money), but be careful: any change in beer/yeast consistency will mess with your numbers. Best way is still with cell counts and volume. Our pilot brewery has made a great yeast brink similar to the one described above. They have added a small continuous mixer (for cell counts), insulation and glycol ports to hook to an existing refrigeration system. Be careful with Corny kegs, all those little places to clean.
I have been using cornys for years. I find it to work very effectively as long as much care is taken to clean and sanitize. Hit everything with heat and chemical sanitizers as often as you can. Before harvest fill corny keg completly with sanitizer and blow out with CO2. If you got a good acid based no rinse sanitizer, this will work very good as well as 50-100 ppm oxine. All the filling, rinsing, and cleaning should be done through your harvesting tool, through the liguid tube in the corny. I use a stainless corny fitting, 3/8 braided tubing, a stainless ball vave, and tank addapter. Make sure to flow cleansers, sanitizers, and heat through the gas tube.
As far as harvesting and pitching, know your system. Know how much yeast each strain produces. Measure this with buckets or calibrated holding tank. A little messy, but gets the job done. You want the middle third. If you brew often get the yeast from beer warmer than 60F. Seems to flow better. (highly flocculant yeast especially) You can use yeast from colder beer as well, just takes longer to harvest. Pull off the bottom third. On a 15bbl system this is usually 15-20 gallons. The yeast should look very clean and healthy at this point. Get a floor scale that can handle 60 lbs use a decent bathroom scale if you're budget minded, or you can get a larger kitchen type scale with large platform for about $100 from a commercial kitchen supply place. Weigh the corny empty and begin to harvest. The rule of thumb is 1 lb per bbl. I find this to work. You will find your zone in no time. A little more for older yeast and a little less for very active yeast. You should be able to harvest at least 25lbs/corny, so you'll probably need only 1 at a time. If you want to harvest for a few brews, go ahead and store them in a cooler, around 35F, if it's a little warmer, don't stress too much. Try to use it in a week or two. If you get to the two week point just add a little more yeast and oxygen when you pitch. I pull the cornys into the brewery the day of the brew to warm up slowly all brew long (It's best to harvest the day before....because you never know, don't be surprised with wort ready to be shipped). Get your wort to the right temp and begin to oxgenate. Spary sanitizer on all fittings before attaching them to the corny and to your pitching port (i use the drain on the tranfer hose close to the tank). Put the corny on a scale and check temps again. Pitch after a couple bbls of wort have been transfered. This makes sure the wort is at the right temp and also allows the yeast to be mixed and oygenated properly. Note the starting weight, now begin to pitch. This should be a good start. Works everytime with excellent results. Once you figure out a system, it's very easy.
One final note. Don't ever get lazy with your cleaning and sanitizing protocol. The more the better. You can not clean, heat and sanitize your harvesting tool and cornys too much. Keep everything packed with acid or sanitizer when not in used (cornys filled with sanitizer make cleaning the harvesting tool a breeze after a brew day)
Ever brewer does things differently. This has worked for me successfully. Hope this helps you.
Flying Fish Brewing Company
yeast storage between uses
At the brewpub I used to work at where we produced ~220 gallon per fermenter (open), we would collect the yeast into stainless steel milk cans, and store in the dispensing tank room. Milk cans are easier to work with and sanitize than corneys and shouldn't be that difficult for you to find.
I've used 10 gal. cornelius kegs for yeast storage hundreds of times. If you're confident in your cleaning protocol/employees it should never be a problem. I would harvest up to 48 hrs. before I needed to repitch. (store in cold cooler) I would strongly suggest you use sanitary methods to harvest. I used latex gloves sprayed down with 70% ethanol. (Everclear/All-grain works too) I would also squirt 70% ethanol on the tank fittings and corney fittings. A high temp. braded hose can be sterlized with steam or 180F+ water for 20 min. Then use a siphon method to run sanitizer through and leave soaking in sanitizer. A bucket gathering method can get messy and very prone to wild yeast infection problems. Acid washing this yeast will never kill the wild yeast. If your harvesting out of a tank that can withstand slight pressure, a clean sanitized brewing hose (w/ BF valve) hooked to your FV outlet works great. Discard the first "yeasts" until the yeast is nice and creamy. Hell, go ahead and taste it. I have only used the weight method while working at a large regional brewery where blending was used often. A better method is to take a cell count. I have the luxury of using a GenPrime unit which tells me how much yeast to pitch based upon vitatlity/viability. This unit also takes the OG into consideration. You would be very surprised at how the pitching levels change depend upon yeast consistency, vitality, etc... Therefore I would never use weight to determine pitching levels. A simple haemocytometer and microscope will give a better idea of cells pitched (but not live cells unless staining is employed) Typically you would want 1 million (live) cells per 1ml/1 degree Plato. So a 13 Plato beer would need 13 million cells/ml. When you pitch use CO2 to push out yeast. You can also release pressure on the corney and force beer back into Corney(use a Tee and another BF valve) to get mixing and any yeast left in the bottom and push back into FV. Hope this helps.