Removing yeast from such cold hibernation and heating it rapidly may shock the cells and reduce the speed of fermentation, with undesirable results.
Gentle treatment will allow yeast to initiate fermentation at the correct time and speed. This is only a guide and pitching rates will increase for strong beers to overcome the inhibition of high alcohol concentrations. Lager yeasts typically require higher pitching rates than do ale yeasts. Lower pitching rates are associated with slower starts to fermentations, higher rates of yeast reproduction, and greater ester production; the converse is true of higher pitching rates.
Brewers determine, based on a number of factors, what pitching rate is best for each beer. Water is not advisable, as it will not neutralize any contamination that manages to find its way into the airlock. The liquid level in the airlock can change and cause some of the liquid to go back into the fermenter which can infect your batch if you do not use cleaner or vodka.
The red cap on bubbler type airlocks does not interfere with the mechanism of the airlock, and can be left on. This will act as a barrier to prevent any dust from reaching the liquid in the airlock. All Rights Reserved. Shopping Cart Shopping Cart View cart.
Beer Starter Kits. Recipe Kits. We recommend using an increased pitch rate when pitching harvested yeast from a previous fermentation versus laboratory grown culture See Pitch Rates section. Laboratory grown culture will arrive in optimum condition for a quick and healthy fermentation. Yeast harvested from a previous fermentation is coming from rather harsh conditions.
The culture can be void of sterols, enzymes, and glycogen, as well having possible poor cell membrane health. When re-pitching harvested yeast, we recommend using the traditional rule of:. When a microscope and proper lab equipment are not available, achieving proper pitch rates involves some guesswork and trial and error.
With some simple guidelines to follow, a brewery without a lab can get consistent results when pitching harvested yeast. Estimates of cell counts can be made using percent yeast solids of the slurry. Percentage of yeast solids per volume of slurry can be estimated by allowing a sample to sediment under refrigeration and estimating the percent solids. 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.
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