Granite Roots Brewing

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PET compared to glass as containers for craft beer

PET is the material used to make 2 liter plastic soda bottles. It has been used for 30 years to store, transport, and consume carbonated beverages.

Before Granite Roots decided to use PET in our 32  ounce growlers along with 16 ounce bottles, we did research and our own testing.

RESEARCH:

  • PET does not contain any BPA.
  • It is a recyclable #1, widely accepted by most municipal recycling centers
  • It is lightweight so when you carry it, it is less stressful on you.
  • It is less expensive to purchase than glass
  • It is cheaper to transport then glass
  • It does not break as easily as glass.
  • Brown PET blocks the same amount of light as brown glass
  • You can take it places where glass is not allowed due to glass breakage
  • The beer containers we purchase are much more ridged then the 2 liter soda bottles and hold their shape.
  • The thick PET also reduces loss of carbonation.
  • A Life Cycle Analysis shows a 12 ounce PET bottle has less of an environmental impact than either aluminum or glass 12 ounce container.
  • Today’s plastic screw on caps make better seals then metal screw on caps. There is no gas permeation through the cap material itself.
  • Lab research shows no significant loss of carbonation after 3 months in standard beer quality PET growlers. Most research shows detectable loss of carbonation in the 3-5 month time frame. So, do not use PET to cellar condition beer. Beer in PET should be consumed within 3-4 months from the time of bottling. This works well for most growlers sold in tap rooms.

I talked with 3 craft breweries who were using PET for growlers. They all said they were glad they have used PET though all said they had to educate customers to why PET was equal or superior to glass except for long term storage.

TESTING:

Granite Roots worked with another local brewery to do testing of a light bodied craft beer in glass and PET 64 ounce growlers. We chose a light body beer because we thought it would show any subtle differences in flavor/appearance. Beer was poured from a tap into both growlers, screw capped and put in a refrigerator for 3 weeks.

Taste tasting after 3 weeks showed no difference in; carbonation level, flavor loss, or off flavor gain between glass and PET.

We have kept a PET bottle filled with a Red Berry Gulp around for up to two months and had good beer poured from that PET container. Sorry, we have not been able to control ourselves to hold the beer longer than 2 months, people keep drinkin’ it!

STORAGE CONDITIONS:

Always keep beer below 80F, preferably below 70F no matter what the container material is.

Keep all beer out of the sunlight since sunlight has the most UV. Artificial light (incandescent) does have some UV but not nearly as much as sunlight. Florescent lightbulbs have almost no UV component.

The PET does have more chance to allow CO2 to escape. Open and enjoy the beer within 1 week for maximum carbonation with minimal oxidation.

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What we do

We're a nano brewery that creates small-batch fruit and traditional beers with fruit and some hops from our farm. Our brewery in Troy, NH opened July 25th 2015!