Category Archives: Homebrew Hacks

Vacuum Sealing Mylar Bags Using FoodSaver Vacuum Sealers

foodsaver mylar bags

Vacuum sealing with a FoodSaver, Seal-a-Meal or similar is a great way store food, hops, grains, spices and more. Vacuum bags work to seal out oxygen, prevent freezer burn and more.

What Are the Advantages Mylar Bags?

Generally speaking Mylar bags consist of three layers. Two Mylar layers that laminate a center aluminum foil layer. This combination provides strength, flexibility and durability along with an extremely low Oxygen Transmission Rate (OTR). These bags also block potentially damaging light. Combine this with vacuum sealing and you’ve got an outstanding way to store food & more.

Search Amazon for “food grade mylar bags” – to see lots of current offerings

For homebrewer’s… Vacuum sealed Mylar bags are an excellent  way to store hops and other oxygen sensitive materials.  As a testament to this, many hop distributors distribute hops in Mylar bags.  Sometimes those are vacuum sealed and sometimes they are nitrogen flushed.

Do Mylar Bags Work with FoodSaver Vacuum Sealers?

A FoodSaver (or similar) is a standard home suction type vacuum sealer that relies on special bags. We generally call them… vacuum sealer bags. These bags are embossed or textured to create channels on the inside of the bag. Those channels allow a FoodSaver to draw out air and create a vacuum all while the machine is clamped down. When this process is done a heat strip seals the bag locking in the vacuum state.

Mylar bags have smooth walls. Since they don’t have the required special channels they will not work with FoodSaver machines.

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Build a Spunding Valve! – How and Why

June 26, 2024

A Spunding Valve allows you to maintain a set pressure.  If pressure in the vessel exceeds the set point, it is expelled.  It generally consists of an adjustable PRV valve, a tee, a gauge and a way to connect to your keg.

Homebrewing Applications of a Spunding Valve

  • Pressurized fermentation.  Ferment in a 5 or 10 gallon corny keg and use your Spunding Valve instead of an airlock.  This allows you to ferment at your desired pressure.
  • Dry hop under pressure.  This allows you to dry hop earlier while reducing oxygenation.  Active yeast are more likely to metabolize oxygen that’s introduced during dry hopping during active fermentation.  Since CO2 is not exiting beer as vigorously under pressure, wanted compounds, flavors and aromas are more likely to stay in your beer under pressure.
  • Naturally and accurately carbonate beer right in the keg.
  • An airlock replacement.  Keep the valve wide open for non-pressurized fermentations.  Only do this if you have plenty of head space.  This wouldn’t make a great blow off tube.
  • Keg to keg transfers.  Use the Spunding Valve to allow excess gas to exit the receiving keg as you transfer under pressure.  Helps you achieve a slow, controlled and pressurized transfer.
  • Fix over-carbonated beers.
  • Test for keg leaks.  Pressurize your keg to serving pressure.  Put the Spunding Valve on (with the pressure set well above your serving PSI) and note the reading.  The gauge should remain steady.  If pressure drops, you know you have a keg leak.  The digital build, see below, is especially helpful for this task,  The digital gauge reads with .1 PSI resolution making pressure changes easy to spot.  It’s worth noting that this checks the entire keg including gas body o-ring.  That spot is hard to check and other way as it’s only in function when the gas QD is on.  When the gas QD is on… it’s difficult to spray and check for bubbles underneath the gas QD.  Thanks to Scott Janish for this tip!
  • As an airlock for long term aging of beers.  Airlocks can run dry over time.  A Spunding Valve will not.
  • Utilize CO2 from fermentation for flushing kegs and fermenters.


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