Thursday 31 August 2023

Beginner FAQ: How to determine the alcohol content of homebrewed beer?

As a homebrewer you'll typically want to know how much alcohol is contained in the latest batch of precious beer that you have fermented, and thankfully the process for working this out is fairly simple.

As we know, the process of brewing beer involves extracting the sugars from malted grains (and sometimes other fermentable ingredients called adjuncts). It is these sugars that are consumed by the yeast during fermentation that create (amongst other things) the byproducts ethanol (alcohol) and carbon dioxide gas.

In order to calculate how much alcohol is in the finished beer, we need to know how much sugar has been consumed by the yeast - so we take gravity readings before and after fermentation to determine how much sugar is in the wort (unfermented beer) and the finished product, and run a simple calculation on these numbers to determine alcohol content.

How is gravity measured? There are several tools or instruments that can be used to do this, but by far the simplest and cheapest is to use a floating hydrometer (pictured below). Simply take a fluid sample in the sample tube, and insert the floating hydrometer into the tube. It will float and show the gravity reading where the stem protrudes from the sample solution.

An example of a floating hydrometer reading 1.000 in plain water

Gravity is measured as a decimal number, with 1.000 being the gravity reading of water. As sugar is added to water, this number will increase. The higher the number, the more sugar is present in the water. A typical starting gravity is referred to as Original Gravity (OG) and in brewing terms is often around 1.040-1.060 for most beer styles. There are of course exceptions on either side of this, but this range is a rough starting point to give some perspective on the numbers we're talking about.

A floating hydrometer reading an Original Gravity (OG) of around 1.064

Original gravity can be measured using a floating hydrometer or refractometer with fairly accurate and reliable results (assuming you're hydrometer is accurate/calibrated correctly to begin with). This can be fairly easily checked by measuring water to confirm your gravity reading device reads 1.000.

At the end of fermentation, a subsequent gravity reading is taken, with the number expected to be much closer to 1.000. This is referred to as a Final Gravity (FG) reading. The lower this number is, the more sugar has been consumed by the yeast and the more alcohol will be present in the finished beer.

An example of a digital refractometer

Since the finished beer has alcohol present in it, refractometers are not as accurate/reliable for obtaining readings as the alcohol will distort the refraction of light, leading to inaccurate results. There are calculators available to account for this, but we'd recommend sticking with the aforementioned floating hydrometer as it's still an accurate method for measuring the final gravity of beer when alcohol is present (without any additional calculations), so this is your best bet especially when starting out.

The formula you need to use is the difference between the Original Gravity (OG) and the Final Gravity (FG) multiplied by 131.25, which will give you the Alcohol By Volume (ABV) as a percentage.

For example, if our OG was 1.045 and the FG was 1.010, the formula would be;

(OG - FG) x 131.25
(1.045 - 1.010) x 131.25
.035 x 131.25
= 4.59%

Pretty simple in the end, and if you don't feel like breaking out your calculator there are loads of online calculators you can use where you just enter the OG and FG values and click a button and it will give you the reading.

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Tuesday 29 August 2023

Keg King - Apollo Titan 30L - Guest Review

The following review was forwarded to us from Kenneth, so we've decided to publish it here in addition to our own review of the same Keg King Apollo Titan 30L stainless steel conical fermenter.

Keg King Titan 30L

After looking at several stainless steel unitanks on the market I finally settled on the Keg King
Titan. I would recommend this unit to ANYONE wanting to upgrade to a stainless fermenter. Don’t
bother with the stainless bucket types. You will eventually want to either spund at the end of
fermentation or close transfer to a keg. Anything that can’t easily handle 10-15 PSI at a minimum
is a waste of money in my opinion. The more expensive bucket versions aren’t much different in
price and the Titan has a more versatile and better design.

I had my reservations about the plastic lid but after seeing other reviews for much pricier
fermenters and problems with lids sealing I decided best to go with what I know works. Good time
to mention I previously was using the Keg King 30L Apollo PET fermenter. The price of the Titan
was very attractive and the gift card I got for Father’s Day last year was a bonus. Out of the box I
could do everything I was doing with my PET Apollo with but with piece of mind I would only need
to buy once. No more worrying about possibly scratching the PET, no more worrying about if my
cleaning water is too hot, no more worrying about pressure testing at expiry date or buying a
replacement tank, and no more worrying about how I can reuse another plastic tank (my old 35L
Fermentasaurus tank makes for a great grain hopper extension). I rinse and clean with 68C water
because that’s what my kettle defaults to for mash in and I am too lazy to adjust it. I have run up to
95C water through my CIP set up with no issues. I didn’t push beyond that because I didn’t want to
cavitate the pump.

As a closed bottom fermenter as it is out of the box, 4.5 stars easy. Only drawback is the damn dry
hop port! I think most users of the Apollo are like me and only use this to fill their vessel. 12.5mm
silicon hose fits great here but more than a few hop pellets at a time not so much. Easier to just
open the lid and chuck them in. It’s a first world problem, but if you’ve designed it one way it should
work that way. More on possible improvements coming below.

As a unitank I really went back and forth on the rating here. Mostly because I was a bit annoyed
that I couldn’t get all the accessories from Keg King at the same time I purchased the fermenter.
When I purchased they did not have the 1.5 inch 90° TC elbow and to this day still do not have a
carbonation stone. Luckily, Cheeky Peak did have both at the time. I’ll settle on 4+ stars for not
having all the accessories and still no solution for that damn dry hop port.

In the end I bought the following accessories:

  • 1.5 inch TC sight glass - Don’t bother buying this. I got caught up in the moment of having something new and shiny and saw other people using sight glasses and thought I needed one too. YOU DON’T. When dumping your trub/yeast simply attach a barbed TC fitting with a small amount of clear hose to help direct where you’re dumping. You will see in the hose when the trub/yeast has gone to beer. If you wait for the sight glass to fill you are simply wasting beer you don’t need to.
  • 1.5 inch TC to 13mm barb. As stated above I use this dumping trub/yeast and also when I set up my CIP loop.
  • 1.5 inch TC to male cam lock. This is to connect to the line from my chiller and fill the vessel. Could probably also be used for dumping trub/yeast and has a slightly wider opening than the 13mm barbed fitting.
  • 1.5 inch TC butterfly valve. Handle fits well between the body of fermenter and legs keeping it easy to use.
  • 1.5 inch 90° elbow - Works perfect and with the butterfly attached the butterfly valve sits perfectly square to the edge of the fermenter.
  • 1.5 inch 45° elbow - another thing I bought and did not need. I thought it would maybe help with trub blocking but I have had no problems with the 90 and it just feels awkward when you attach it.
  • Extra 1.5 inch TC clamps and seals. I would recommend having at least two more clamps than what you need. Seals I think I got an extra 5 or 6. They are both cheap so better to have extras than not.
  • 1.5 inch TC carbonation stone - works great. Use it for both aerating wort and carbonating. I was concerned with it possibly blocking being in the fermenter during fermentation and after cold crash but have not run into any problems yet. If it does become blocked I am not too worried about it. It’s not a required piece for this to operate as a unitank as you can still carbonate through the gas disconnect in the lid. Just won't be as efficient. A non-return valve would be nice (looking at you Cheeky Peak if you happen to read this).
Just a few additional observations and recommendations for use or if a V2 is ever made.

  • Need a bigger version for double batchers. I have several mates that want one of these but they only double batch.
  • The TC port on the body of the fermenter I haven’t quite found a need for. This would be much better on the top of the fermenter for easier dry hopping. Did I mention I hate the dry hop port on the lid? Bottom port I have 90 elbow to butterfly clamp to cap. The cone TC port is where I opted to put the carbonation/aeration stone. Everything else you need/want is in the lid, except a bigger dry hop port of course.
    If you are looking to harvest yeast you will find the fewer the side ports the better. Why you ask? When you break down your fermenter you’re going to find that each of these ports has a shadow to them and a lot of that great clean yeast is sitting in that shadow and never made it’s way to the bottom of the fermenter to be collected.
  • I love the simplicity and affordability for such a versatile product. When looking at other stainless fermenters it was crazy to me how many of them out of the box you couldn’t carbonate in or do a closed transfer without buying an accessory kit or pack first because it won’t work at even 10-15 PSI out of the box. Many of these were more expensive and less functional out of the box than after I bought the accessories to complete my unitank and that includes the pieces I didn’t need and don’t use.. This has three TC ports and one sits unused. I think I saw one other fermenter that had three TC ports just in the lid! Why? So I can buy more stuff I won’t use. I also watched a Youtube review of another and there was talk of people making sculptures and putting 4-way TC pieces on top. Again, Why?
  • The legs and extensions need two things. One, more holes for adjusting the rough height of the extensions and adjustable feet for finer adjustments.
    Two other things to consider. A fourth leg and welding to the outside of the body rather than the cone. Don’t get me wrong, I have no issues with the stability but more stability would be better than more TC ports I won’t use.
  • I mentioned my CIP set up a couple of times. I used the lid from my Apollo fermenter and attached a sprayball to the inside of the lid where the thermowell was. The top of the lid I attached a cam lock and run the CIP with a 25 watt mag drive pump. I have also run foaming sanitser through this set up for up to 10 minutes without the foaming becoming a problem.
Hope you find this review helpful. It was a lot for me and probably for a lot of others to invest in a
stainless steel fermenter, but I would highly recommend the Titan for any brewer looking to
purchase a stainless steel fermenter. Best combination of value and function that I found by far.

Friday 11 August 2023

Are your keg O-rings causing oxidation? KegLand Low2 seals

KegLand have recently released an interesting video on YouTube claiming that the silicone O-rings they have been including with their corny kegs as the seal for the main keg opening have been tested and believed to allow significant amounts of oxygen to leech through them and into the keg.

The video itself is well worth a watch, as Kee from KegLand interviews Bruce Gunn, the owner of GunnLab Plastics Testing Pty Ltd and discusses the testing they performed and associated results. KegLand commissioned GunnLabs to perform a controlled test of their silicone keg O-rings to measure oxygen ingress from outside of the keg lid to the inside of the keg, and discovered that the silicone that these are made of allowed worryingly high amounts of oxygen to permeate through them.

Image from the GunnLab report showing the test being performed

As you can see from the image above, for the test they cut the top of a keg and welded it to a flat metal sheet underneath. A full size keg couldn't be used as the volume/capacity inside it would be too large for the testing machine to accurately measure.

The report has been published on the KegLand website, and shows (among other things) that the silicone O-rings (white in colour) allow transmission of 11.3cm³ ox oxygen per day through them.

As you would expect, KegLand have developed another O-ring which is yellow in colour and constructed of different materials to address this issue and are referred to as "Low2" seals . In it's testing it allowed 0.41cm³ of oxygen per day to permeate through. A fairly significant difference by any measure when compared to the results of the white silicone O-rings.

The new re-designed keg O-rings are yellow in colour
Image Copyright of KegLand

While the numbers for the white O-rings seem quite high, it's worth noting that this is based on a test where the seal is exposed to 100% oxygen for the duration of the test, so under regular atmospheric conditions the actual number would be around 21% of this (which is the percentage of oxygen in normal air). We should also point out that the report mentions they didn't check if any oxygen ingress occurred through the pressure relief valve (PRV) or ball lock posts on the lid itself, but given the significant difference in readings by changing only these seals over, it's reasonable to assume any oxygen ingress through the other openings in the keg lid would be negligible.

So why is this important? Well, for finished beer (ie. beer that has completed it's fermentation) - oxygen is public enemy number one, with even the smallest amounts of oxygen causing an effect called oxidation which leads to discolouration, off flavours and essentially ruins the beer. Brewers go to great lengths to avoid their finished beer coming into contact with oxygen, by using processes such as pressure transfers to essentially eliminate O² contact and ingress. Having oxygen leak through the O-rings potentially brings all this hardwork undone - a chain is only as strong as its weakest link and all that.

Admirably, KegLand are admitting that the silicone O-rings they've been selling are problematic and are offering an "amnesty" where they are including some of their new yellow O-rings to customers when placing an order on their website by including a special promo code. You can of course just buy them separate if you wish - they're currently selling for $4 each on the KegLand website.

Some common myths and misconceptions were also addressed in the YouTube video - like the theory that because kegs are typically presurrised with carbon dioxide gas (CO²) this will provide protection against oxygen ingress, however this is not true. Although the keg is kept under pressure, materials like silicone will still allow air and oxygen to travel through them - regardless of the pressure on either side. This isn't indicative of a leak in the seal, but rather the gas permeating through the seal itself.

So is it time to hit the panic button and cease all brewing and kegging operations until you've replaced your seals? We don't think so - we're actually mildly skeptical of the severity of this problem. We're certainly not debating the accuracy of the test results, but perhaps there's a bit more to it. You can see from the photo in the GunnLab report (also included at the top of this page) that only the top section of a corny keg lid was used and welded to a sheet of steel providing a relatively small keg 'body' where the oxygen levels were measured from. In a full size corny keg, however, if oxygen leaks through the lid seal at the top, does it mix evenly with the carbon dioxide gas and come into contact with the beer? Or does the heavier CO² gas form a 'blanket' over the surface of the beer, with the lighter oxygen molecules floating above it at the top of the keg and therefore not coming into contact with the beer itself?

We're not sciency enough to know the answers to all of this, but what we do know is that we've had beers stored for months in kegs using the silicone O-rings for months without any oxidation issues. Of course we've experienced some oxidized batches in the past but put it down to other poor practices/mistakes rather than an issue with the keg seal allowing oxygen ingress, and no doubt there are hundreds of other brewers who have had similar experiences. The type of beer you're storing can also determine it's susceptibility to oxidation with more hop forward styles being more severely affected.

Will we be replacing the seals in our kegs anyway? Absolutely - with KegLand offering the O-rings for free with orders that are placed that include a special promo code, it certainly makes sense to take advantage of this. And if you miss out on the free offer, at only $4 each for a new seal it's undoubtedly a worthwhile and relatively cheap investment to help reduce the chances of any kegged beers suffering the effects of oxidation.

And while KegLand didn't mention any other particular brands of keg manufacturers, it's probably reasonable to assume that other brands are susceptible to the same problem, so regardless of what keg you're using it's probably worthwhile changing your seals over.

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