Troubleshooting - I Can't Pour: Guinness Edition

I Can’t Pour: Guinness St. Patty’s Day Edition

Ahh, St. Patty’s Day. That lovely time of year where everyone is a little bit Irish and a lotta bit drunk and disorderly. I worked at an Irish pub here in a Helena for a bit before I found my calling at McDantim as a sarcastic goofball who talks a lot. I had the singular distinct displeasure of working on St. Patrick’s Day shortly after being hired (Reminder: tip your bar staff enormously on St. Patty’s Day because walking through shoulder to shoulder crowds on a sticky floor trying not to spill beer while people are gesticulating like maniacs to get the bartender’s attention is not my idea of a good time.)

Every year, traditionally the day of or before St. Patrick’s Day, we’ll get phone calls about how the Guinness is pouring. Most times, happily, we can solve the issue quickly and the end user continues their merry way, shillelaghs and all. Unfortunately, we run into larger problems that need time to fix, which doesn’t exactly work for a tavern’s busiest day of the year. “I tried to pour my Guinness and it’s pouring like a milkshake,” or “I have to put Guinness on for the weekend on my 100% CO2 system. That should work, right?”

Fun Fact: McDantim got its start from Guinness’ quest to have the perfect mixed gas blend to dispense their liquid gold Guinness stout. We even have a commendation from Guinness for our product (shameless plug.)

Guinness, for peak pour-formance (my apologies,) uses a 25% CO2 / 75% N2 blend at around 35 psi. This combination results in the wonderful cascade of nitrogen bubbles and the creamy tawny foam. Now, let’s say you try to put Guinness on your 100% CO2 system with the same 35 psi, your carbonation level of 1.1 v/v skyrockets to 4.59 v/v. Thus, milkshake. Unfortunately, there isn’t enough time allotted in the day and half before St. Patty’s day to settle the keg, nor get a new one from your distributor and have it cold and unjumbled.

Here’s my plea, as a Guinness drinker not only on St. Patty’s Day: Check your Guinness several days before St. Patty’s and the bookending weekends so you can get the most out of your kegs and customers.

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McDantim's Troubleshooting blog is written by Kayla Mann, our Marketing Assistant.

Kayla has been with McDantim since April 2015. She has an English Literature degree and very strange internal dialogue.

If you have any suggestions for what topics our blog should include, or have stories that can expand our topics, please email