Aseptic yeast transfer apparatus and method
A yeast storage and transfer vessel having semi-permeable materials and a method for transfer of liquid yeast to a fermentor using said vessel and a peristaltic pump. In some embodiments, one or more opening(s) may include a port and valves and/or filters allowing the egress of carbon dioxide and other fermentation gases out of the yeast vessel. The bag storage vessel materials may also include semi-permeable materials. The herein disclosed apparatus and method permit the sterile transfer and mixing of yeast and/or fermentation product into a variety of fermentors, in addition to sterile pumping action in the reverse direction.
1. A yeast vessel, comprising:
a yeast connector, and yeast storage bag;
said yeast storage bag comprising yeast storage bag walls and a yeast storage bag periphery, the yeast storage bag walls having an external structural layering and an internal structural layering, the yeast storage bag periphery including laser perforations that blends the external structural layering and the internal structural layering, allows CO2 to vent out of the yeast vessel, minimizes the ingress of oxygen back into the yeast vessel and allows the yeast vessel to function under repeated fluctuations in pressure and temperature;
the yeast storage bag walls further comprising PET laminate materials;
said yeast connector further comprising a cap adapter; and
said yeast connector comprising at least one port having an opening and a filter in sealing engagement with the port adapted to support an aseptic transfer of liquid yeast under a range of temperature and pressure conditions, the port adapted to reseal the yeast vessel under aseptic conditions, permitting semi-permeable efflux of carbon dioxide out of the yeast vessel.
2. The yeast vessel of claim 1 , wherein the internal structural layering includes clear LDPE.
3. The yeast vessel of claim 1 , wherein the external structural layering including 6 mil PET laminate.
4. The yeast vessel of claim 1 , wherein the yeast storage bag is adapted to store a quantity of liquid yeast ranging between 500 ml and 3 L, preferably between 1 L and 2 L.
5. The yeast vessel of claim 2 , wherein the unidirectional valve is semi-permeable to carbon dioxide, permitting carbon dioxide egress out of the yeast vessel.
6. The yeast vessel of claim 1 , wherein the walls of the yeast storage bag are comprised of material selected from the group consisting of polyurethane, laminated polyethylene, polyolefin, ethylene-vinyl acetate copolymer, polyvinylidene chloride, and/or a coextrusion of polyethylene and polyvinylidene chloride.
7. A yeast vessel, comprising:
a yeast storage bag comprising yeast storage bag walls and a yeast storage bag periphery, the yeast storage bag walls having an external structural layering and an internal structural layering, the yeast storage bag periphery including laser perforations that blends the external structural layering and the internal structural layering, allows CO2 to vent out of the yeast vessel, minimizes the ingress of oxygen back into the yeast vessel and allows the yeast vessel to function under repeated fluctuations in pressure and temperature;
a yeast connector;
the yeast connector and yeast storage bag support aseptic yeast transfer into fermentors;
the yeast connector and yeast storage bag remaining fully functional following more than one hundred transfer cycles and under low pressure conditions, the yeast storage bag having yeast storage vessel walls further comprising PET laminate, said yeast connector comprising at least one port adapted to reseal the yeast vessel under aseptic conditions; and
a valve in cap engagement with the at least one of the port, the valve allowing egress of fermentation gases, thereby enhancing yeast health and minimizing contamination by microorganisms.
8. The yeast vessel of claim 7 , comprising an inside surface of the at least one port defining an opening, and means of connection to quick connect fittings for engagement with ½″ silicone tubing to support aseptic transfer of liquid yeast to a fermentor under a range of temperature and pressure conditions common to standard brewing operations.
9. The yeast vessel of claim 7 , further comprising a filter of temperature-resistant, pressure-resistant, chemically resilient, and/or electrochemically resilient materials, thereby supporting aseptic transfer of liquid yeast to a fermentor.
10. The yeast vessel of claim 7 , the yeast storage bag and yeast connector further comprising:
a yeast storage bag nonporous top surface and bottom surface, a first opening in said top surface;
the valve and/or filter disposed over said first opening, permitting escape of fermentation gases from said yeast vessel, said first opening having a Gurley porosity in the range of 2 to 120 seconds and disposed such that the egress of all gases from said yeast vessel during fermentation must pass through said first opening;
a liquid inlet means disposed over said second opening, providing a means of liquid flow into said yeast vessel;
a bottom opening in said bottom surface;
liquid outlet means disposed over said bottom surface opening, providing a liquid outlet from the yeast vessel; and
a cap adapter providing a reversible means of transferring out of and into the yeast vessel.
11. The yeast vessel of claim 10 , wherein a filled yeast vessel comprises at least 1 billion yeast cells/ml, preferably 2 billion yeast cells/ml.