Aerator Disc Comparison 1

Introduction

This is the first post in a series where I will try to find what (to me) results in the best pint of Guinness. First up I plan to test different aerator discs. Eventually, I will test different faucets, pouring methods, and glassware.

Part of the process of pouring a nitrogen beer is pouring it through an aerator or creamer. This is a disc with holes punched through it that the beer is forced through. In theory, the size and number of the holes could have an impact on what ends up in your glass. To test this out I purchased a set of aerator discs. For this first test I am comparing the disc with three 0.3 mm holes and the disc with three 0.7 mm holes.

Testing Method

• Each disc is installed on a different stout spout. This is just to make switching between pours easier. Other than the disc, the spouts should be the same.
• Before pouring a pint I will run off some beer. This should ensure that there are no variations in the temperature of the faucet between the first and second pour.
• I poured each Guinness by holding the beer close to the faucet at a about a 45 degree angle, aiming to hit the center of the harp. Beer was poured until it reached the top of the harp (while being held at a 45 degree angle which is roughly the bottom of the harp when the glass is upright) then I set a timer for two minutes. When the timer went off I poured to the top of the Harp and then immediately turned the handle backwards and poured to the top of the glass.
• Once each beer was finished I let them rest for at least five minutes to let the temperature stabilize.
• I did my initial tasting without knowing which pour was which. For this first test I actually had to close my eyes as it was quite easy to distinguish the pours from each other.

Comparison

The 0.3mm disc is slow. After run off I had to double check my pressure and ball valve. After the first pour the head goes from just above the bottom of the harp to almost the bottom of the Guinness text. Because the pour takes so long you have less time to enjoy the cascade effect after putting the glass down to let it settle.

After finishing the pour the size of the head looked good. But there was a noticeable dimple.

Conversly, the 0.7mm disc took about 15 seconds for the first pour. The head was a little smaller than the Guinness poured with the 0.3 mm disc. The top of the head was just above the bottom of the harp. The bottom was (to use an industry term) splitting the G.

And after topping off the head was again smaller compared to the 0.3mm disc:

After allowing the beers to settle further, the Guinness poured with 0.3mm fell quite a bit below the lip of the glass. And there was still a noticeable dimple. The Guinness poured with the 0.7mm disc had about the same size head but the bubbles looked tighter. Here’s a comparison with 0.3mm on the left and 0.7mm on the right.

And a top down view again with the 0.3mm disc on the left and the 0.7mm disc on the right:

Now the most important part: how did they taste. For me, the 0.3mm disc was thinner all around. It seemed less creamy and the flavors did not pop as much. They were both good pours but I definitely preferred the Guinness poured through the 0.7mm disc.

Conclusions

The 0.7mm disc was the clear winner. It poured at a more normal pace and (in my opinion) it both looked and tasted better.