Category Archives: Airlocks

Kegland BlowTie Diaphragm Spunding Valve – $26.99 + free shipping + Hands on Review

Diaphragm Spunding Valve - Adjustable Pressure Relief Gauge Ball

Diaphragm Spunding Valve – Adjustable Pressure Relief Gauge Ball

More Info

From the product description, check product page for current description, price and availability:

The BlowTie Spunding Valve is used to release excess pressure on a pressurized fermenter or from a keg while doing pressure transfers. Thanks to the large surface area of the diaphragm, this style spunding valve is much more accurate than the poppet style. 8 mm Duotight fittings at both inlet and outlet make this unit perfect for use with EVABarrier 8 mm OD tubing. The blow off pressure can be set by either pairing the BlowTie with the included Push-In Pressure Gauge, or by attaching it to an empty keg that has been pressurized to the desired psi.

Made from food grade acetal
Stainless screws
Easily disassembles for cleaning
8mm (5/16″) Duotight fittings at both ends
0-40 psi pressure rating
Two functions in one great piece of hardware!

The Ball Lock QD Adjustable Pressure Valve W/Gauge can also be used to relieve pressure while filtering from one keg to another. At the same time it gives you the ability to read the pressure in the receiving keg. And Ferment under desired pressure!

 

Spunding Valve Applications
  1. 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.
  2. 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.
  3. Naturally and accurately carbonate beer right in the keg.
  4. 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.
  5. 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.
  6. Fix over-carbonated beers.  Use the same general process as for carbonation (skipping the addition of fermentable sugar).  Use a carbonation chart to determine proper pressure for the temperature the keg is at.  The Spunding Valve allows excess pressure to vent until the new carbonation level is achieved.  You can agitate the keg to fix carbonation more quickly.
  7. 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.  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!
  8. As an airlock for long term aging of beers.  Airlocks can run dry over time.  A Spunding Valve will not.

 

Lots more about Spunding Valves on our Spunding Valve Build Resource Post

As if this posting, this is eBay offering is selling for $26.99. Shipping is also free to many US addresses.  Prices, shipping and availability can change quickly. Please note that product prices and availability are subject to change. Prices and availability were accurate at the time this this post was published; however, they may differ from those you see when you visit the product page. Check the product page for current price, description and availability.

Diaphragm Spunding Valve – Adjustable Pressure Relief Gauge Ball

Check out my Hands on Review of this great assembly!  Hands on Review: Kegland BlowTie Diaphragm Spunding Valve!

Also: Kegland DuoTight Push-In Fittings & EVABarrier Double Wall Draft Tubing at MoreBeer

More: Recent Great Deals

prod:ebay2btsp

1/4″ NPT Male x 1/4″ SAE Male Stainless Fitting – $6.99 + free shipping & Building a Spunding Valve

HFS (R) Twin Fitting, Adapter 1/4" male SAE 37 Degree Flare to 1/4" Male NPT ; Stainless Steel 304

HFS (R) Adaptor Stainless Steel S 304 3A (1/4″ NPT – 1/4″ SAE)

A Spunding Valve allows you to ferment under pressure, naturally and precisely carbonate in the keg, fix over-carbonated beers and more.  See: Build a Spunding Valve for more info.  Take a look at Build Option 2 for a version that uses this fitting.  A photo of this fitting as part of a Spunding Valve build is to the right.  Note: The description of this has changed since I first purchased it in October of 2018.  At that time it was titled HFS (R) Twin Fitting, Adapter 1/4″ male SAE 37 Degree Flare to 1/4″ Male NPT ; Stainless Steel 304. 

7/12/19 2 AM Central: This is available again for just $6.99. Shipping is also free to many US addresses. Prices, shipping and availability can change quickly. Please note that product prices and availability are subject to change. Prices and availability were accurate at the time this post was published; however, they may differ from those you see when you visit Amazon. Check the product page for current price, description and availability.

HFS (R) Adaptor Stainless Steel S 304 3A (1/4″ NPT – 1/4″ SAE) – note that multiple variations of this product may be available, as such a different version may appear at this link


More: Recent Amazon Finds

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.  prod:B014UJEVUG

SIX x 3 Piece Fermentation Airlocks – $7.61, $1.27 Each + free prime ship

3 Piece Plastic Airlock (Sold in sets of 6)

6 x 3 Piece Fermenter Airlocks


From the product description, check product page for current description, price and availability:

  • Airlock, three piece airlock, wine bubbler, beer bubbler
  • Simple to use
  • Easy to clean

7/7/19 4 AM Central: These are selling for just $7.61. Shipping is also free to many US addresses with Prime Membership [Try Prime for Free] or a qualifying order. Prices, shipping and availability can change quickly. Please note that product prices and availability are subject to change. Prices and availability were accurate at the time this post was published; however, they may differ from those you see when you visit Amazon. Check the product page for current price, description and availability. Also: Recent Amazon Finds and Amazon Fillers Resource Page 

Home Brewing Supplies 48-9AJX-W965 Econolock-6pk Airlock, Clear


Related: Yeast: The Practical Guide to Beer Fermentation & Best Sellers in Lab Erlenmeyers – via Amazon | StirStarter Stir Plate | Yeast Starters and Fermentation Resource Page

More: Recent Amazon Finds


UPDATE – Hands on Review: Kegland BlowTie Diaphragm Spunding Valve! – Purge Kegs w/CO2 Produced by Fermentation

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.

Why a Spunding Valve?

There are loads of homebrew related applications for a Spunding valve ranging from pressurized ferementation to naturally carbonating to fixing over carbonated beers and lots more.  Check out our resource post on the subject.  It’s arguably the go-to resource on the Internet on the subject

Hands on Review Kegland BlowTie Spunding Valve

The BlowTie Spunding Valve assembly consists of the BlowTie, a DuoTight Tee Fitting, a DuoTight to flare fitting, a DuoTight pressure gauge and two small pieces of EVABarrier Tubing.

Here’s a look at each component…


Get the Gear, Review Continues Below:


The BlowTie is the heart of this build.  It has DuoTight Push to Connect connections on both side as well as an adjustment knob to set pressure. Continue reading

16 x Silicone Food Grade Airlock Grommets – $6.95, w/coupon + free prime ship

Masontops True Fit Silicone Grommets For Mason Jar Fermentation Airlock Lids, Sauerkraut, Kimchi, Homebrewing, Wine and Beer Making - 16 Pack

Masontops True Fit Silicone Grommets For Mason Jar Fermentation Airlock Lids, Sauerkraut, Kimchi, Homebrewing, Wine and Beer Making – 16 Pack

More Info

From the product description, check product page for current description, price and availability:

  • INCLUDES 16 TRUE FIT GROMMETS – Ideal for mason jar fermentation, standard airlocks, mason jar straws and other accessories, wine making and beer brewing.
  • DESIGNED FOR PLASTIC AND METAL MASON JAR LIDS – It may seem like a simple component, but we have taken the time to get the sizing, flex, and shape just right for a durable, safe grommet that is easy to insert and remove over and over again.
  • BPA-FREE, FOOD-GRADE, REUSABLE AND DISHWASHER-SAFE – True Fit Grommets are made from premium clear silicone. They can be safely reused over and over and are dishwasher-safe
  • DIMENSIONS – Center Hole – 3/8″ diameter (9 mm), Center Channel – 1/16″ width (1.5 mm), designed to fit 9/16″ lid holes (14 mm).
  • EASY TO INSERT AND REMOVE – Simply punch or drill a 9/16″ (14 mm) hole in your mason jar lid and insert the grommet edge into the opening so that the grommet groove catches on the edge.

 

Use to add an airlock port to a container of your choosing.  Most of the grommet offerings I see don’t claim to be food grade.  That’s probably not a big deal considering that most of the time this gets little to no contact with your beer.  Having said that, it’s nice to have a food grade option.

7/3/19 3 AM Central: These are selling for $8.95. Click on “Save an extra $2 when you apply this coupon” and the price drops to just $6.95.  Shipping is also free to many US addresses with Prime Membership [Try Prime for Free] or a qualifying order. Prices, shipping and availability can change quickly. Please note that product prices and availability are subject to change. Prices and availability were accurate at the time this post was published; however, they may differ from those you see when you visit Amazon. Check the product page for current price, description and availability. Also: Recent Amazon Finds and Amazon Fillers Resource Page

Masontops True Fit Silicone Grommets For Mason Jar Fermentation Airlock Lids, Sauerkraut, Kimchi, Homebrewing, Wine and Beer Making – 16 Pack – note that multiple variations of this product may be available, as such a different version may appear at this link


Related: Yeast: The Practical Guide to Beer Fermentation & Best Sellers in Lab Erlenmeyers – via Amazon | StirStarter Stir Plate | Yeast Starters and Fermentation Resource Page

More: Recent Amazon Finds

FIVE x Three Piece Airlocks – $6.92, $1.38 each + free prime ship

3 Piece Plastic Airlock (Sold in sets of 3)

Set of 5 Three Piece Airlocks.  Use on your fermenter to help prevent outside air from backflowing.

7/2/19 7 AM Central: These are selling for $6.92.  Shipping is also free to many US addresses with Prime Membership [Try Prime for Free] or a qualifying order. Prices, shipping and availability can change quickly. Please note that product prices and availability are subject to change. Prices and availability were accurate at the time this post was published; however, they may differ from those you see when you visit Amazon. Check the product page for current price, description and availability. Also: Recent Amazon Finds and Amazon Fillers Resource Page 

3 Piece Airlock (Qty. 5)


Related: Yeast: The Practical Guide to Beer Fermentation & Best Sellers in Lab Erlenmeyers – via Amazon | StirStarter Stir Plate | Yeast Starters and Fermentation Resource Page

More: Recent Amazon Finds

Ready Made Spunding Valve from William’s Brewing – $23.99, Save 20% + stacking deal

0-15 ADJUSTABLE PRESSURE RELIEF VALVE

Adjustable Pressure Relief Valve Assembly via William’s Brewing


From the product description, check product page for current description, price and availability:

This adjustable pressure relief valve has a sensitivity of 0 to 15 psi. It has a 1/4″ female flare fitting on one end, which attaches to any threaded ball or pin lock gas fitting. Use this to make a keg pressure relief valve. Adjust the relief pressure by turning the knob on the right side of this assembly. Also known as a Spunding Valve.


A Spunding Valve has lots of applications…

Spunding Valve Uses
  1. 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.
  2. 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.
  3. Naturally and accurately carbonate beer right in the keg.
  4. 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.
  5. 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.
  6. Fix over-carbonated beers.  Use the same general process as for carbonation (skipping the addition of fermentable sugar).  Use a carbonation chart to determine proper pressure for the temperature the keg is at.  The Spunding Valve allows excess pressure to vent until the new carbonation level is achieved.  You can agitate the keg to fix carbonation more quickly.
  7. 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.  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!
  8. As an airlock for long term aging of beers.  Airlocks can run dry over time.  A Spunding Valve will not.

Lots more about Spunding Valves on our Spunding Valve Build Resource Post

 

If you’ve been eyeing our Spunding Valve Build, but don’t want to put it together yourself, here’s your chance.  William’s Brewing generally has this for $29.99.  Check the product page for current price, description and availability.

As of this posting, William’s Brewing has a summer clearance sale going on that discounts a large selection of items by 40%.  Note: discounted prices are reflected in your cart.  No coupon or promo code is required.  Check William’s for current selection and availability.

See: Summer Clearance at William’s Brewing

This sale saves you 20% and makes this pre-built Spunding Valve $23.99.

0-15 ADJUSTABLE PRESSURE RELIEF VALVE

Update: This promo has expired or pricing, availability or description has changed – Check the supplier’s site or product page for current availability

Recent Deals!  Last Fifty Finds

Also Consider: Build a Spunding Valve! – How and WhyHands on Review: Kegland BlowTie Diaphragm Spunding Valve


Visit William’s Brewing – Web Only Clearance Sale

Recent William’s Brewing Finds [view more]:

rp:wmsspunding

Kegland BlowTie Diaphragm Spunding Valve – Complete Assembly… $27.99 + free shipping + $5 off $50 promo & Hands on Review

pin lock spunding valve

Kegland BlowTie Diaphragm Spunding Valve – Adjustable Pressure Relief Gauge Ball

More Info

From the product description, check product page for current description, price and availability:

These are purpose built high quality valves KegLand. Not just hardware store pieces like the competitors.

The BlowTie Spunding Valve is used to release excess pressure on a pressurized fermenter or from a keg while doing pressure transfers. Thanks to the large surface area of the diaphragm, this style spunding valve is much more accurate than the poppet style. 8 mm Duotight fittings at both inlet and outlet make this unit perfect for use with EVABarrier 8 mm OD tubing. The blow off pressure can be set by either pairing the BlowTie with the included Push-In Pressure Gauge, or by attaching it to an empty keg that has been pressurized to the desired psi.

Specifications:
Made from food grade acetal
Stainless screws
Easily disassembles for cleaning
8mm (5/16″) Duotight fittings at both ends
0-40 psi pressure rating
Two functions in one great piece of hardware!

The Ball Lock QD Adjustable Pressure Valve W/Gauge can also be used to relieve pressure while filtering from one keg to another. At the same time it gives you the ability to read the pressure in the receiving keg. And Ferment under desired pressure!

If you prefer it sent with a Pin Lock type quick disconnect instead of the ball lock, please leave a note to seller at checkout, otherwise we will ship with ball lock type.

 

Spunding Valve Applications
  1. 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.
  2. 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.
  3. Naturally and accurately carbonate beer right in the keg.
  4. 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.
  5. 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.
  6. Fix over-carbonated beers.  Use the same general process as for carbonation (skipping the addition of fermentable sugar).  Use a carbonation chart to determine proper pressure for the temperature the keg is at.  The Spunding Valve allows excess pressure to vent until the new carbonation level is achieved.  You can agitate the keg to fix carbonation more quickly.
  7. 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.  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!
  8. As an airlock for long term aging of beers.  Airlocks can run dry over time.  A Spunding Valve will not.

 

Lots more about Spunding Valves on our Spunding Valve Build Resource Post

A ball lock qd is pictured.  If you’d like a pin lock version, just leave a note for the seller at checkout.

As if this posting, this is eBay offering is selling for just $27.99. Shipping is also free to many US addresses.  Prices, shipping and availability can change quickly. Please note that product prices and availability are subject to change. Prices and availability were accurate at the time this this post was published; however, they may differ from those you see when you visit the product page. Check the product page for current price, description and availability.

Kegland BlowTie Diaphragm Spunding Valve – Adjustable Pressure Relief Gauge Ball

Check out my Hands on Review of this great assembly!  Hands on Review: Kegland BlowTie Diaphragm Spunding Valve!

Stacking Promo: As of this posting, Lion Brewing Solutions is giving you $5 off any $50 order when you like their Facebook page, while you’re at it… connect with HBF on Facebook.  Just like the page and enter a note at checkout saying “I liked your Facebook page, I’ll take my $5 off $50” along with your name on Facebook.  Lion Brewing Solutions will confirm you like their page and refund you $5 from your $50+ purchase.  Limited to one use per Facebook account.  It’s worth noting that this applies to everything.  Even items and lines that are not typically discounted.

$5 Off $50 at Lion Brewing Solutions – with FB like

Also: Kegland DuoTight Push-In Fittings & EVABarrier Double Wall Draft Tubing at MoreBeer

More: Recent Great Deals

prod:ebaybtsp

Kegland BlowTie Diaphragm Spunding Valve – Complete Assembly… $27.99 + free shipping + $5 off $50 promo & Hands on Review

Kegland BlowTie Diaphragm Spunding Valve - Adjustable Pressure Relief Gauge Ball

Kegland BlowTie Diaphragm Spunding Valve – Adjustable Pressure Relief Gauge Ball

More Info

From the product description, check product page for current description, price and availability:

These are purpose built high quality valves KegLand. Not just hardware store pieces like the competitors.

The BlowTie Spunding Valve is used to release excess pressure on a pressurized fermenter or from a keg while doing pressure transfers. Thanks to the large surface area of the diaphragm, this style spunding valve is much more accurate than the poppet style. 8 mm Duotight fittings at both inlet and outlet make this unit perfect for use with EVABarrier 8 mm OD tubing. The blow off pressure can be set by either pairing the BlowTie with the included Push-In Pressure Gauge, or by attaching it to an empty keg that has been pressurized to the desired psi.

Specifications:
Made from food grade acetal
Stainless screws
Easily disassembles for cleaning
8mm (5/16″) Duotight fittings at both ends
0-40 psi pressure rating
Two functions in one great piece of hardware!

The Ball Lock QD Adjustable Pressure Valve W/Gauge can also be used to relieve pressure while filtering from one keg to another. At the same time it gives you the ability to read the pressure in the receiving keg. And Ferment under desired pressure!

If you prefer it sent with a Pin Lock type quick disconnect instead of the ball lock, please leave a note to seller at checkout, otherwise we will ship with ball lock type.

 

Spunding Valve Applications
  1. 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.
  2. 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.
  3. Naturally and accurately carbonate beer right in the keg.
  4. 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.
  5. 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.
  6. Fix over-carbonated beers.  Use the same general process as for carbonation (skipping the addition of fermentable sugar).  Use a carbonation chart to determine proper pressure for the temperature the keg is at.  The Spunding Valve allows excess pressure to vent until the new carbonation level is achieved.  You can agitate the keg to fix carbonation more quickly.
  7. 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.  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!
  8. As an airlock for long term aging of beers.  Airlocks can run dry over time.  A Spunding Valve will not.

 

Lots more about Spunding Valves on our Spunding Valve Build Resource Post

As if this posting, this is eBay offering is selling for just $27.99. Shipping is also free to many US addresses.  Prices, shipping and availability can change quickly. Please note that product prices and availability are subject to change. Prices and availability were accurate at the time this this post was published; however, they may differ from those you see when you visit the product page. Check the product page for current price, description and availability.

Kegland BlowTie Diaphragm Spunding Valve – Adjustable Pressure Relief Gauge Ball

Check out my Hands on Review of this great assembly!  Hands on Review: Kegland BlowTie Diaphragm Spunding Valve!

Stacking Promo: As of this posting, Lion Brewing Solutions is giving you $5 off any $50 order when you like their Facebook page, while you’re at it… connect with HBF on Facebook.  Just like the page and enter a note at checkout saying “I liked your Facebook page, I’ll take my $5 off $50” along with your name on Facebook.  Lion Brewing Solutions will confirm you like their page and refund you $5 from your $50+ purchase.  Limited to one use per Facebook account.  It’s worth noting that this applies to everything.  Even items and lines that are not typically discounted.

$5 Off $50 at Lion Brewing Solutions – with FB like

Also: Kegland DuoTight Push-In Fittings & EVABarrier Double Wall Draft Tubing at MoreBeer

More: Recent Great Deals

prod:ebaybtsp

Hands on Review: Kegland BlowTie Diaphragm Spunding Valve!

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.

Why a Spunding Valve?

There are loads of homebrew related applications for a Spunding valve ranging from pressurized ferementation to naturally carbonating to fixing over carbonated beers and lots more.  Check out our resource post on the subject.  It’s arguably the go-to resource on the Internet on the subject

Hands on Review Kegland BlowTie Spunding Valve

The BlowTie Spunding Valve assembly consists of the BlowTie, a DuoTight Tee Fitting, a DuoTight to flare fitting, a DuoTight pressure gauge and two small pieces of EVABarrier Tubing.

Here’s a look at each component…


Get the Gear, Review Continues Below:


The BlowTie is the heart of this build.  It has DuoTight Push to Connect connections on both side as well as an adjustment knob to set pressure. Continue reading