Friday, 25 August 2017

I Can't Believe It's Not Butter

What’s this?

“What do you think of this?” As I arrive for my shift behind the bar my colleague hands me a small pour of a hazy, pale amber beer. His face is expressionless. Is this a test of some kind? I take a couple of sniffs of the beer and say, “It smells like vanilla? Like cream soda?” I take a sip of it. “Urgh. It’s so sweet. What is it? It tastes like artificial sweetener. It’s gross. What is it?” I hand it back. He names the beer. I recognise the name, it’s an IPA from a British brewery. I’m not 100% sure I’ve tried this specific beer before but I know no IPA should smell or taste like that.

The following week I taste a DIPA and immediately an epic battle commences in my mouth between BITTERNESS and OVERWHELMING SWEETNESS (not just sweet but sickly too, like artificial sweetener). It’s unpleasant to the point of being unenjoyable. Later on I ask some friends what they think of the same beer. One confidently says, ‘yeah, that's got diacetyl'; the other agrees, adding ‘it’s so buttery’. 

After this particular exchange I am approaching the end of my personal Journey of Realisation - that I’m not immune to diacetyl after all. I just perceive it differently to pretty much every other person I’ve ever discussed it with over the years.

While I'm getting my head round the idea that my vanilla =  everyone else’s butter a couple of previous episodes of ‘funny tasting beer’ come drifting back, where pale ales and IPAs tasted of vanilla to me but not to anyone else. I even know someone who won a medal for a homebrewed saison that tasted like cream soda to me. I knew it didn’t taste right at the time but I couldn’t have said what the specific fault was then (other than saisons shouldn’t taste of cream soda, obviously). But I could now.

Until this day nobody had EVER mentioned vanilla to me in relation to diacetyl. I had even asked a couple of brewers, specifically what could give rise to vanilla as an ‘off flavour’ and nobody knew. When I tweeted about my recent experience someone tried to tell me it was a commonly used descriptor for diacetyl, but I have never seen it before. Once I got home I started going through the brewing library. Luckily Dr George Fix came to the rescue (1). While discussing the preference some people have for beers with prevalent diacetyl he notes that:

“The vanilla tone, which is often confused with caramel flavoring, definitely adds to the smoothness of beer.”

Ah, so it's not just me then. Well, that's a relief.

Special Relationship

At this point I should mention that before I switched to a career in biomedicine I used to work in a QC/chemical analysis lab at Yoplait Dairy Crest where I was known as a bit of a vanilla super taster - I am very sensitive to low levels of vanilla. Part of my role was tasting products to check they matched their specification, to detect if there was too much or too little flavouring in the final product. If you were lazy you could cheat and judge visually for flavours like strawberry or cherry but because vanilla yogurt is white you can't tell by looking - you can only tell by taste.

But even before I had my professional experience with vanilla, I had already come to love it as a child who did a serious amount of baking. In fact, for most of my early teens I thought I was going to become a professional baker of some kind when I left school. I actually used 'cake mix' as a beer flavour descriptor recently because to me it's shorthand for 'smells like a rich, sweet perfumy batter'. Perhaps in future I’ll just learn to say ‘urgh, diacetyl’ instead.

So, yes, I love vanilla but the flavour completely spoils pale ales and IPAs for me.

Utterly Butterly

So what is diacetyl? As mentioned above it is generally recognised as an off flavour in beer, although it is acceptable in certain styles, e.g English bitters, Scotch ales or Czech pilsners. The standard description for the flavour is ‘buttery’, but you will also find ‘butterscotch, caramel, creamy, milky’ mentioned. Diacetyl can also be experienced as a mouthfeel sensation - it can be perceived as ‘slippery’ or ‘slick’.
The commercial use for diacetyl is literally making things taste like butter. Anything which is meant to taste like butter, from margarine to Butterkist, will be flavoured with diacetyl.
Diacetyl is a natural byproduct of fermentation. You cannot eliminate it so the key is to control its presence in beer styles where it should not be evident. Fortunately, yeast is capable (depending on strain) of reabsorbing diacetyl and converting it into more palatable compounds. The simplest way for brewers to avoid diacetyl in their finished beer is to start fermentation with a sufficient amount of healthy yeast and provide the right conditions for the yeast to do its work. Once fermentation is almost complete, raising the temperature will allow the yeast to ‘clean up’ the finished beer. This process is called a ‘diacetyl rest’ and is especially important for lagers.
However, diacetyl it is also produced by species of lactic acid bacteria, Pediococcus and Lactobacillus. So unintentional diacetyl in a finished beer may indicate a contamination issue in the brewery, or in lines/taps at the point of dispense. This contributes to the negative reputation of diacetyl.

So what is wrong with my palate?

Short answer: I haven’t found out yet. I’ve participated in many off flavour tasting sessions, from both sides of the table, and (until now) diacetyl has remained the one major off flavour that I have struggled with. I’ve never been 100% confident that I can detect it in the kinds of beers I like to drink, although I seem to 'get it' alright when using the off flavour kits. When discussing the fault in commercial beers other people have always said they get ‘butter, caramel, butterscotch, popcorn’ and I just go, ‘um...I don’t it really sweet?’ When your answer is different to everyone else’s you tend to think that you’re wrong and you just don’t get it. But perhaps that isn’t always the case.

In Essence

I began to wonder how vanilla and butter could be confused as the same flavour. One is sweet, the other is fatty. One is worn as a fragrance, the other is exclusively a foodstuff. I still can't make sense of it.

As a vanilla lover I have previously explored the differences between vanilla extract (which contains natural flavour from vanilla beans extracted into ethanol) and vanilla essence (which is usually synthetic vanillin). Natural vanilla flavour is comprised of hundreds of components of which vanillin is the most prominent. If anyone wants to get into the science of artificial vs natural flavourings (both vanilla and butter) in a bit more depth then I highly recommend the Kennedy article, linked below (2).

Vanilla has a striking aroma which can be overwhelming when overdone but at lower levels is warm and comforting, maybe even romantic. Do you find a Victoria sponge cake to have a striking vanilla character? Possibly not but it’s definitely in there somewhere and it’s an integral part of its overall cakeyness. In fact, most so-called ‘plain’ or ‘white’ sponge cakes and cupcakes contain vanilla flavouring because it's used as a flavour enhancer - it gives us that impression of naughty sweetness which we desire and expect. 

Answers on a postcard

The purpose of this post was to share my strange experience of finally 'getting' an off flavour after all these years. I have held back the scientific detail on diacetyl and vanilla as none of it really explains why I get vanilla or artificial sweetener instead of butter (but I'll definitely keep looking for the answer to that).

I'm keen to hear from anyone else who has had a similar experience of getting a completely different impression of an off flavour to the one which is cited by almost everyone else they have ever mentioned it to. I feel as if I must have a loose connection somewhere.


1.Principles of Brewing Science (Second ed.) George Fix. (1999) 

Thursday, 13 April 2017

Beeromatherapy: the science of hop aroma

We run the homebrew club at We Brought Beer and back in February we gave a presentation called Hoptimisation - The Science and Process of Hop Aroma. I was pleased to build on my existing knowledge of hops and learn more about why some of those hop aromas seem strangely familiar. In fact I found it so fascinating I thought I'd share my enthusiasm for it here.

Monday, 13 February 2017

LOL sexism in beer

I've tried to resist devoting any more of my time to writing about sexism in beer, partly because I don’t believe it is going to change any minds and partly because I'm bored of the subject. However, there have been some unpleasant and disturbing opinions aired recently which I don’t feel like simply ignoring.

Now, I know that often the people saying these horrible things are looking for a reaction. In some cases that actually seems like the main point for them - rather than having very strong feelings on the subject itself. On the whole I try to avoid rewarding attention seekers but it would be difficult to write this without referencing the sources.

Friday, 5 August 2016

The Sciencing of Beer in a Post-Fact Society

Same but Different


The recent release of Cloudwater’s double IPA v4 and v5 raised some interesting points which go beyond arguing over which is the best DIPA in the UK. I’m not reviewing these beers here because what I am actually more interested in is the wider concepts relating to the release of these beers, i.e. crowd sourcing opinions on how to develop future beers, taking one beer and changing exactly one specific element of the process (AKA The Scientific Method) to get two different beers, and planning the sequential development of a beer over multiple iterations. 

Wednesday, 11 May 2016

A Beautiful Cloudiness


Our server deposits a flight of beers on our table: a bespoke wooden tray holding a number of small glasses filled with varying degrees of amber. I lean forwards in my seat, ever hopeful, lifting the first glass to my nose. I take a long sniff, followed by a couple of sips. Then I sigh; place the glass back in the tray and slump back in my seat. ‘I’d rather be drinking a Kernel IPA,’ I say and not for the first time on this trip.

Tuesday, 26 April 2016

The Best Double IPA in the UK

April has seen us drowning in double IPA. If you enjoy this style of strong, super hopped IPA then you’ve been spoiled for choice in the past few weeks. I’ve seen and heard a lot of beer nerds talking about which of them is 'the best DIPA'. Of course this is what beer lovers are into – discussion and friendly argument about beer. But I am surprised that people are still talking about this in terms of absolutes, as if one beer has to be awarded the title of ‘The Best’ and all the others must therefore be 'less good' beers. As if there isn’t a place for variation of expression within a style; as if context is irrelevant. By all means choose a favourite, choose one beer that you prefer above the others. But does one really have to be the best and the others all inferior to it as a result? I don’t think it’s that simple and I don’t really believe in absolutes.

Sunday, 31 January 2016

We Brought Homebrew: IPA edition (now with added entry requirements)

We're pleased to announce that we're going to run linked sessions for February and March at the We Brought Beer Homebrew Club. The February session (Feb 16th) will be on the critical appreciation of beer (we have special guest, Chris Hall joining us) and the March session (Mar 15th) will be about judging beer. In order for club members to get the most out of these two sessions we have invited them to brew an IPA and bring it along to the March meeting where it will be judged by all attendees. This can be any type of IPA, e.g. single, double, triple IPA, Belgian IPA, black or white IPA. It can be a clone of a famous example of the style, a revisit of a traditional recipe, or something entirely new. The beer can be all extract or all grain or anything in between. The only limiting factor for the beer is that it must be broadly recognisable as an IPA. We are brewing our own entry today. 

We are really looking forward to trying all the entries. But first, we'll be putting on our thinking caps for the next meeting and learning how to taste beer. Make sure you bring your notebooks.

Will you brew a clone of a famous IPA?

IPA Challenge: Entry Requirements 

If you are planning on bringing an IPA (which you have brewed) to enter in the IPA Challenge on March 15th then please do the following things in order to assist us with the organisation on the night:
  • Bring your entry upstairs as soon as you arrive so that we can assign you and your beer with an ID No. and get them in the fridge asap
  • Do not label your bottles as we wish to keep everything anonymous
  • Bring at least 2L of your beer so that we have enough for a number of people to judge each entry
  • Let us know what the ABV is - this is so that we can split the entries evenly across different groups
  • If you haven't already done so then PLEASE email us in advance to let us know you're entering and style of your IPA as this will save time on the night
  •  PLEASE NOTE we are going to have to limit the number of entries we are able to judge. In order to guarantee your entry please let us know asap that you will be entering a beer, as we may not be able to accept any further entries on the night.
Any questions about this session? Email us (see below).

For more information about the homebrew club please go here. If anyone is thinking of attending and would like to ask us anything feel free to drop us a mail or tweet:

NB: If you're brewing an IPA for the March session or you've already attended the club and you're brewing something else you can use the hashtag #wbbhbc so that we can see what you're getting up to.