Using Polypropylene Lab Bottles to Rehydrate Yeast

Bel-Art Precisionware Wide-Mouth 500ml (16oz) Autoclavable Polypropylene Bottles; Polypropylene Cap, 53mm Closure (Pack of 12) (F10632-0007)Pictured: (12) 500 mL Polypropylene Jars with 53 mm closures by Bel-Art Products – via Amazon

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  • Note: This tip involves handling hot items.  Always use extreme caution when handling hot items to avoid being scalded.
  • In my opinion, Polypropylene is a good material for this.  It is commonly used in lab bottles and has a higher heat resistance when compared to HDPE and LDPE.
  • The pictured bottle is what I personally use.  There are lots of options out there.  Search Amazon for Polypropylene Lab Bottles to see what else may be available,  Some things to look for – proper temp ratings, use of food safe materials and microwaveable.
  • Consult your yeast manufacturer for specific amounts, temperatures and timing recommendations.

Rehydrating Yeast Step by Step

  • Place the appropriate amount of water in the bottle.  Some manufacturers recommend 10 grams of water per 1 gram of yeast.  Most packets are 11 grams.  That’s 110 grams.
  • Use an accurate gram scale to weigh the water.  For a common measurement like 110 grams, I mark my bottle with a Sharpie so I can easily measure out rehydration water without needing to weigh every time.
  • Place the lid on top of the bottle.  Important: Do not thread or tighten the lid!  It will burst if you do that.  You just want the lid setting loosely on top so that it can be sanitized by the steam.
  • Microwave until the water comes to a full boil.
  • Cooling to Temp, Slow Option: Let the bottle sit with cap loosened until it reaches proper hydration temperature.
  • Cooling to Temp, Quick Option: Very carefully tighten the cap down.  Run cool water over the bottle to reach proper rehydration temp.  This is going to be hot, be very careful!  I use heat resistant gloves for this.  The cooling will most likely cause the container to collapse on itself and could slightly misform it.
  • I use an Infrared thermometer to check temp as cooling commences.  Note that I do not open the bottle to check temp.  Just aim the IR thermometer at the mass of water inside the bottle.  I’m usually aiming for around 95 deg F.
  • Sprinkle the dry yeast in the container and place the lid on back on the bottle.  Let this sit for 10 to 15 minutes.
  • Gently swirl bottle to ensure the yeast is thoroughly mixed.
  • Pitch when you’re ready.
  • This method ensures a sanitary process.  The initial container and water are sanitized and there is no touching of the water with thermometers or stirring devices.
  • You could use a similar method to produce yeast washing water.
  • Search Amazon for “Polypropylene Lab Bottles” – Some things to look for – proper temp ratings, use of food safe materials and microwaveable.
  • Search Amazon for “digital gram scale”
  • Search Amazon for “infrared thermometer”
  • Search Amazon for “heat resistant kitchen gloves”
  • Review: Hands On: American Weigh 100g x 0.01g Digital Scale
  • Related Categories: YeastScales, Infrared Thermometers

Make sure the components you use are compatible and rated for your intended application.  Contact manufacturer with questions about suitability or a specific application.  Always read and follow manufacturer directions.

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