Introduction
This is the fourth 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. In my last test I compared a disc with three 0.7mm holes to one with one 0.7mm hole. It was hard to pick a winner and this test is likely to be even harder.
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 near the top of the glass (while being held at a 45 degree angle) then I set a timer for two minutes. When the timer went off I poured the beer straight down while pushing the tap handle forwards until beer reached near the top of the harp then pushed the handle backwards to top off.
- Once each beer was finished I let them rest for to let the temperature stabilize.
- I did my initial tasting without knowing which pour was which.
Comparison
My first pour was with the 0.5mm disc. I did some testing with my coffee scale and found that this poured at a rate of about 5 grams per second. It took roughly 30 seconds for the Guinness to reach the bottom of the harp and another 30 seconds to reach the top of the glass (while the glass was held at an angle).
The second pour was with what is becoming ol’ reliable: the disc with three 0.7mm holes. The flow rate on this was at least three times as quick: showing 15-17 grams per second on the coffee scale.
After allowing both pours to settle they (as expected) look very similar. Though the 0.5mm disc has bubbles that are a little less packed together. Here’s a side by side with the 0.5 mm disc on the left and the 0.7 mm disc on the right:
With the top down view you can see that the Guinness poured through the 0.7mm disc has larger bubbles (the fact that it was poured last probably has an impact on this). But if you ignore the spot made by the beer contacting the liquid in the glass I think it looks smoother overall:
Conclusions
The first test I did was with the 1×0.3mm disc and the 3×0.7mm disc as I figured those two would have the widest spread in results. Since then, the 3×0.7mm disc has been my preference every single time. For this test, I intentionally poured with the 3×0.7mm disc second in case I was preferencing the first pour for a reason other than the disc (like it being slightly warmer).
Despite that, I still prefer the disc with three 0.7mm holes. No surprise, this test was the hardest to distinguish a difference. And I still don’t think I’d be able to reliably pick these out in a triangle test. The 0.5mm disc had the same sort of micro foam texture that I’ve been enjoying with the 0.7mm disc. But the 0.7mm disc just had more of it.
At this point, I expect the 0.7mm disc will win out. But I haven’t tested a disc with 5 holes yet. And the two discs I have remaining are the 3×0.5mm and the 3×0.3mm. Maybe one of those will dethrone the 3×0.7mm.