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Q&A on Gas

by | Jan 29, 2013 | 1 comment

Last week ‘n did a post on a potentially dangerous situation that I encountered at a roastery. In response, I’d like to run through a few typical Questions & Answers that could help roasteries out there understand gas better and make more informed decisions when installing gas systems for their roasters.

I invite all roasters to send me more questions, better answers or any piece of information that could help other roasters with regards to gas. Please feel free to comment below this post!

Questions surrounding gas

So what can owners do to protect themselves from possible unsafe gas situations?  Here are some tips for any existing and prospecting roasters.

Products

1. Who installs and pays for the gas installation?

Typically the owner is responsible for all costs pertaining to the installation of the gas train.  The onus also falls on the owner to review the local health and safety guidelines and municipal codes regarding gas installation and safety. I have seen commercial installations that cost around R2000 or more, but it largely depends on your particular setup, the size of your roaster and how many bottles you want.

You HAVE TO get a certified gas technician to install your gas.  Depending on your property’s location, you may also have to get a fire marshal in to certify your installation.  Ask your gas installer for advice and make sure that he gives you an original Gas Compliance Certificate once the installation is complete.  This certificate is similar to an electrical certificate that an electrician issues after inspecting your property.  The whole process can take well over 2 weeks, so make sure you budget enough time for inspection and installation before your roaster arrives.

Remember that if your installation does not comply with local regulation, your insurance will NOT cover you should a fire occur.  As legal fiduciary you can be held liable for any damages or injuries sustained because your installation is not properly certified.

2. What gas should I use

For coffee roasters, it is our recommendation that you use Propane gas as opposed to Liquified Petroleum Gas (LPG).  Propane is a little more expensive but burns hotter and cleaner than LPG (in SA).  Therefore you get very little of any residual gassy taste in your coffee while getting more bang for your buck (no pun intended) by using pure Propane.

In contrast, LPG is a mixture of Propane and Butane gas.  Because of the density difference, suppliers often change their Propane:Butane mixture from 60:40 to 40:60 depending on the season and exact ratios can also differ from day to day.  This gives LPG a bad rep as its combustion temperate constantly changes.  If you have carefully plotted roast profiles, you’ll need to adapt your roasting parameters constantly to get the same results.  The difference may be minuscule, but if you want the edge above your competitors, you’d better be prepared to go the extra mile.

3. How do I know if the gas runs empty

On a Genio, spotting an empty cylinder is pretty easy: just look at the control panel’s gas gauge.  If it does not reach the usual maximum, you know that there is less pressure which usually means an empty cylinder.

Genio Gas Gauge

On normal setups, your installer will give you 4x or 6x 48kg gas cylinders.  The cylinders will be installed in a steel cage outside your building.  The 4x cylinders are split into a left and right supply line.  If the 2x bottles on the left runs empty, simply “throw over” the valve located in the middle and the supply will switch over to the right hand side.  Even if you have 2x or 3x cylinders per side, make sure that all of them are open at the same time.  This equalizes the pressure across the cylinders and ensures that you have a more constant supply of pressure to your roaster.

Here is a typical gas installation compliments of Complete Gas Supplies:

Typical gas installation compliments of Complete Gas Supplies

4. How do I know if my burner’s flame is healthy

A proper roaster, or any burner for that matter, should always have a deep blue flame.  Yellow flames are sure signs of incomplete combustion.  If only a small part of the flame is yellow, you’re still in the clear.  The position of your flame is also important: a flame that “drifts” above your burner points to a lack of oxygen.  Yellow flames will quickly create soot and a buildup of Carbon Monoxide (CO) although you’d have to be pretty darn negligent (read: stupid) to die from the latter.

Genio Mezzo gas burner

Genio always enjoys a good discussion. Please feel free to comment below if you have anything to add!

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1 Comment

  1. Gavin

    HI Neil Maree

    I’m in the process of designing my own hobby roaster and have a question on where I can source the best burners and regulators for my project.

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