This will vary with the yeast strain. By using this method with every brew, a brewer can achieve consistent pitch rates batch to batch resulting in a more consistent product. Once the brewer has determined the desired pitch rate and cell density of the slurry the brewer can collect the appropriate quantity of yeast. Slurry can be harvested based on volume or weight. The following guidelines will deliver the appropriate pitch rates. Yeast Storage Yeast should be used as soon as possible and not stored for long periods before re-use longer than 2 weeks.
Warmer temperatures and oxygen exposure will increase the rate of culture degradation. Excessive pressure can be detrimental to the culture. Extreme care must be taken when cleaning and sanitizing the storage vessel and all associated parts.
Fittings should be disassembled and soaked before every use. A closed harvest and re-pitching procedure will minimize the opportunity for air-born contamination and is recommended if the malt mill is in the same room as the brewery or the mash is a dusty procedure. Cylidroconical Fermenter Storage of yeast for more than 48 hours in a glycol cooled cylindroconical fermenter is not recommended.
Yeast is an excellent insulator and will typically be several degrees warmer in the center of the slurry than at the outside edge. Higher flocculating strains tend to pack more densely in the cone and therefore be more prone to increased temperatures in the center of the slurry. Yeast Brink Usually exclusive to larger breweries, a glycol cooled, agitated yeast brink has many advantages over other collection vessels. The agitation of glycol cooled slurry offers precision temperature control.
A yeast brink allows for easy yeast washing and QC sampling as well as propagation. A yeast brink can either be mounted on a scale or fitted with a flow meter for delivering accurate and consistent re-pitching volumes. Cylidroconical Fermenters: Conical bottomed fermenters greatly improve the ease and efficiency of harvesting yeast. The conical bottom allows for easy trub discharge. Trub discharge should be performed twice prior to harvesting yeast.
The tank should be thoroughly cooled with the yeast settled to a thick slurry before harvesting. When the trub has been discharged and the yeast appears clean, an additional small discharge of yeast should be performed to eliminate the most flocculent and dead yeast. I would think that it would probably be ok for a few months, but I wouldn't push it too far.
I usually try to use it within a month or two at most. I try not to surpass two months Beerontwowheels likes this. HerbMeowing Aspirant Nov 10, Virginia.
Hanglow Champion Feb 18, Scotland. A couple of weeks ago I used some WLP that I had washed, maybe three or four months old, the starter started quick and it smelled great, as does the just now finished beer I made with it. I've seen on HBT and Jim's beer kit a few posters saying it's good up to a year I think resuing yeast is a good idea, either by top cropping or rinsing, especially considering here at least it can cost up to half the price of a batch of beer.
Plus plenty of yeasts can improve over a few generations too. Anybody know how the yeast banks work? I only use it because its so cheap and I figure why not….
Any idea on how long can the harvested yeast can last? I have a jar of harvested yeast that is 2 months old, which I collected using this method, but have not had time to brew, and am wondering if it is still viable. Thanks, Connor. I think this topic is very subjective. But Ive also heard of people using it months later. Make a starter using DME, cool it off, and let your harvested yeast warm up to within degrees of the starter and pitch maybe 72 to 74 degrees.
Let the yeast do its work and once fermentation subsides and settles to the bottom, try decanting the beer off the top, pouring it into a cup, and tasting it. See if you can detect any off-flavors. If not, you should be OK stepping up the starter for brew day. In a perfect world, one would harvest the yeast slurry from batch A and repitch immediately into batch B brewery style.
But most homebrewers dont overlap their batches like that so storage is a must. Good luck!!! One thing I forgot to mention: dead yeast cells tend to fall to the bottom of the fermentation vessel first while healthy cells remain in suspension during fermentation. Therefore, you want to prevent repitching dead cells into your next batch so its wise to discard the lower layer of yeast during collection.
When I buy new yeast, I make a liter starter, put in sanitized jars, mark the date and type of yeast and cold crash in the fridge. One pack of yeast usually gets me beers before I start over. Only once did I open a jar, 4 months old that I felt it smelled off. Never had any infections or off flavors.
It just works for me. Find what works for you and stick with it! Often times, a general beer consumer cannot fully distinguish when a yeast has been used too many times. As homebrewers, we tend to have a better taste for off flavors that we learn over time through experience. So as you mentioned, its best and fairly inexpensive to just taste it and see. AFTER you decant the spent beer from the jar of yeast. Can anyone tell me how fast the yeast that is harvested and kept in a fridge dies?
Is it approximately the same as packaged yeast? Not sure that answers your question, but I just assume similar viability as packaged yeast. Did you have to feed it DME or anything over that 3 months? I know when my wife does a sourdough starter she feeds every 12 hours sometimes. I do a similar thing but fill my jars with Starsan. I always seem to have some mixed Starsan around at bottling. Also dead yeast is a key component in the yeast nutrient we add. I have been top cropping this.
About sanitation: You mention sanitizing your jar that you split the slurry into, which of course makes sense. What type of flask are you using? Do you boil the starter wort in the flask? You only need a slight boil anyway, no need for a hard boil. I boil directly in the flask for only 4 or 5 minutes with no issues. Like Paul said, a couple drops of Fermcap or unflavored and unscented baby gas formula is a MUST when boiling in the flask.
I find a 2 liter is good for vitality starters while 5 liter is better suited for harvesting. Where did you get your 5L flask from? This will reduce both the risk of spoilage and of autolysis. Autolysis is when a yeast cell goes into self-destruct mode and essentially digests itself. This process often produces a rubbery stench that, needless to say, is undesirable in beer.
As mentioned earlier, the yeast should be stored in a container with a loose fitting lid or an airlock. After you collect the yeast and put it in the refrigerator it will not immediately go dormant as most refrigerators are not very cold and the temperature fluctuates considerably over time.
Because of this, yeast stored in a refrigerator may produce some carbon dioxide that could cause problems. To store the yeast at a lower, more stable temperature, place the yeast container in a small cooler or a box with baggies of ice in it.
It is important to vent the container daily, for the first three days, because excessive CO2 will damage yeast quickly. Likewise, some containers may rupture under excess CO2 pressure. Yeast should be used in a batch of beer within two weeks of being collected from a previous batch. Yeast that is not actively fermenting can lose its viability rather quickly when stored using the simple methods and conditions outlined here. This is where scheduling to brew successive batches of beer is important if you wish to collect and repitch yeast.
When you are ready to retrieve your stored yeast from the fridge and pitch it into a new batch of wort it is important to give the yeast a wake up call before putting them to work.
Remove the container with the stored yeast from the refrigerator and allow it to slowly warm up to the temperature of the wort it will be pitched into. You may want to give the yeast a shot of oxygen to help them become active. This can be accomplished by simply stirring the yeast up with a sanitized spoon or whisk to develop a bit of froth.
If you have a magnetic stir plate you can sanitize the stir bar, slide it into the yeast vessel and place it on the stir plate and fire it up. If you have an aquarium pump with an inline sanitary air filter, you could also pump air into your yeast in addition to giving it a stir to provide aeration. Once the yeast has been stirred and had a chance to warm, it can be pitched directly into the waiting wort. A few final considerations for harvesting and reusing yeast relate to beer style.
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