Dry brewing yeast typically contains less than 7% water. Stringent quality standards are applied during manufacturing to avoid microbial contamination. The remarkable stability of dry yeast allows for significant QC testing in order to ensure less than 1 bacterium or wild yeast cell detected per million cells of brewing yeast. For most strains, 1g of dry yeast contains a minimum of 5 billion viable cells, but the number will vary slightly from batch to batch.
Dry yeast is packaged under vacuum in 500g packs or 11g sachets and must be stored dry, below 4˚C (39˚F). Exposure to humidity and oxygen will affect the viability and vitality of the yeast. Do not use soft packs or sachets that appear to have lost their vacuum. Once a pack or sachet is open, use immediately for best results. If kept sealed (or re-sealed) under vacuum and stored under appropriate conditions, dry yeast can be used until the indicated expiration date, which is typically 2-3 years after manufacture.
Upon rehydration, dry cell membranes undergo a transition from gel to liquid crystal phase. Rehydration in sterile water is recommended prior to pitching into wort in order to reduce stress on the cell as it transitions from dry
to liquid form. Proper rehydration of dry yeast will produce a highly viable and vital liquid slurry.
The following effects have been observed with nonrehydrated yeast under specific brewing conditions:
• Longer diacetyl stand
• Longer fermentation time
• Longer lag phase
• Stuck fermentation
• Poor utilization of maltotriose
FOUR IMPORTANT FACTORS TO CONSIDER DURING REHYDRATION
1. MEDIA TYPE
Rehydration in undiluted wort causes osmotic stress to the yeast. Sterile water should be used for rehydration, but distilled water should be avoided.
The ideal rehydration temperature is different for ale and lager strains. Ale strains should be rehydrated at 30-35°C (86-95°F), whereas lager strains should be rehydrated at 25-30°C (77-86°F).
The rehydration period should be between 20-60 minutes. A decrease in viability and vitality will result from extended storage periods after rehydration. Once rehydrated, the yeast can be pitched into wort. To avoid shocking the yeast, the temperature of the yeast should be reduced gradually to within 10°C (18°F) of the wort temperature. This can be achieved through additions of small volumes of wort to the rehydrated yeast slurry.
Care should be taken to avoid contamination during rehydration. The rehydration vessel should be autoclaved or sanitized before use. The outside of the yeast pack and the scissors/knife should be soaked in sanitizing solution prior to opening.
LalBrew® Abbaye is an ale yeast of Belgian origin selected for its ability to ferment Belgian style beers.
LalBrew® BRY-97 is an American West Coast-style ale yeast that was selected from the Siebel Institute Culture Collection for its ability to produce high quality ales.
LalBrew® CBC-1 has been specifically selected from the Lallemand Yeast Collection for its refermentation properties and is recommended for Cask and Bottle Conditioning.
LalBrew® Diamond Lager yeast is a true lager strain originating in Germany.
LalBrew® Munich Wheat Beer yeast is a neutral strain which can be used to produce a wide variety of wheat-based beer styles.
LalBrew® Nottingham is an English style ale yeast selected for its high performance and versatility for a
wide variety of styles and fermentation conditions
LalBrew® New England is an ale strain selected specifically for its ability to produce a unique fruit-forward ester profile desired in East Coast styles of beer.