Monday, 22 May 2017

Dealing with beer haze part two

Though some brewers are now actively encouraging beer hazes, to the extent of doing daft things like adding flour, most beer is still served bright. Following on from this article I wrote for the SIBA journal here's part two.

Dealing with beer haze part two


Having looked at non-microbiological hazes in part one of this article I will now look at hazes caused by microbes and how to avoid them.

Microbiological hazes can be caused by an excess of brewers’ yeast remaining in suspension or a bacterial and/or wild yeast infection. To prevent your own yeast causing problems the first step is to ensure that it is in a healthy state and the correct amount is pitched into the wort. For a beer with a gravity of 1.040 around 10 million viable cells per ml of wort will be required. You will need a microscope to do a yeast count and methylene blue stain to determine viability. Inexpensive microscopes are now widely available and with only a little practice they become easy to use and should become part of your routine. If weighing yeast slurry you will be looking for around 2lbs/bbl or 450g/hl. Yeast counts should also be carried out on beer before packaging. For cask beer it is recommended that the yeast count at racking is 0.5 to 2 million cells/ml.

Good flocculation will get the yeast out of suspension and there are a few things you can do to help it on its way. Calcium is needed for yeast to flocculate so get your liquor treatment right. Auxiliary finings and isinglass finings will both greatly help beer to clarify. Auxiliary finings are negatively charged and using them before adding isinglass, for example in the fermenter, will help the isinglass work well. Isinglass finings have a positive charge and will attract the negatively charged yeast cells and help them settle out. Both these types of finings will need to be used at an optimised dose as under or over fining will give poor results. Your finings provider should be able to help you with finings optimisation if you are unfamiliar with the procedure.

Microbiological hazes can also be caused by infection of bacteria and/or wild yeast. A microscope can be of use in detecting infection, but only if the organisms are present in sufficiently high numbers and further lab-based tests may be required for certainty and to confirm identification.

Using selective culture media grown under specific conditions (aerobically or anaerobically) allows the numbers of organisms present to be determined and identification is easier when looking at the shape of the colonies. Culturing for microorganisms will not give an immediate result as they will take days to grow, but can be very useful both when trouble shooting and as part of a quality assurance programme.

A table of which organisms to look for in different samples is shown below:

Sample type
Microorganisms
Wort
Aerobic + anaerobic bacteria, wild yeast
Yeast
Aerobic + anaerobic bacteria, wild yeast
Green Beer
Anaerobic bacteria
Bright Beer
Anaerobic bacteria
Filtered Packaged Beer
Anaerobic bacteria
Cask Conditioned Beer
Aerobic + anaerobic bacteria, wild yeasts

As can be seen there are many stages at which micro problems can occur and avoiding them requires an integrated approach. Brewery design should minimise chances of cross contamination e.g. keeping malt dust away from fermentation areas. Pipework should avoid dead legs to prevent material that will support microbial growth accumulating and to ensure that cleaning cycles are effective. Plant integrity should be checked regularly and any leaks or perished seals are warning signs of potential problems.

Checks can be made for microbial contamination that give an immediate result. ATP bioluminescence detects a compound found in all living cells and is an excellent marker for microbial organisms. Swabs can be used to check that surfaces have been cleaned effectively and last rinse water at the end of a cleaning cycle can be monitored.

If infection is found in packaged beer then corrective action can only be used to prevent it reoccurring in future brews. But if bacterial infection is found in one if the most common sites, pitching yeast, then acid washing can be used to remedy the situation almost immediately.

Acid washing will significantly reduce bacterial numbers without greatly affecting the health of the brewing yeast if carried out correctly. The yeast must be at a cold temperature before acid washing and it must be kept cold during the process. Slowly add acid (typically 75% food grade phosphoric diluted 1 in 10) to the yeast slurry whilst mixing well until the pH has dropped to between 2 and 2.2. Leave for one hour, stirring regularly, and then pitch immediately. Unfortunately if the pitching yeast is contaminated with wild yeast acid washing won’t help and fresh yeast will need to be obtained.

Regular monitoring of process samples as part of a quality assurance programme is the best way of preventing microbiological hazes in your beer and finding out if there are any particular problem areas in your brewery.

Saturday, 13 May 2017

Magical drinking

Avowed materialist and rationalist that I am I still think that there is something magical about cask beer. As I brewer and scientist I once explained at great length to a wine drinking friend of mine how beer gets its flavour. I went through malt types and grist composition, mashing conditions and fermentability, hop varieties and hop additions, yeast strains and fermentation temperatures, but when it got to cask conditioning I faltered. There's something it can bring to beer that I could only describe as magic. This got short shrift from my friend who'd patiently sat through me droning on about enzymes, IBUs and EBCs and Maillard reactions. But magic was the best word I could come up with.

It only happens occasionally, but it's never happened with anything I've drunk from a bottle, can or keg. The moment when angels descend from heaven to dance on your tongue and exalt the most high is the preserve of cask. It can strike in unexpected places, and with the most innocuous looking of beers. The best pint I ever drank was a national brand in a basic pub on a dull Friday night. And much to my surprise I once passed on the stronger beers in the sample room at Harvey's Brewery to spend an hour drinking only the 3% ABV mild because the good lord had seen fit to send his angels down from heaven and into the mild cask. I wonder if CAMRA theologians have discussed how many angels can fit though a shive hole?

The fact I have to invoke magic to explain the wonders of cask beer does trouble me slightly so I have pondered how exactly they occur. The lack of filtration and pasteurisation must play a part, and along with the lower carbonation and higher temperature compared to inferior serving methods the flavour of the beer is maximised. But why is it that only occasionally the beer goes from being good to truly sublime? And is there anything else that brewers and publicans can do to make it happen more often? As ever, more research is needed. 






Tuesday, 9 May 2017

Tightwads the lot of you

Well, most of you are tightwads anyway. Rather than focus on the harm to craft that Tescos and/or Adnams are doing by flogging off small cans of beer cheap over 80% of you just see a bargain. Though as Mudgie points out what must be around half price the Adnams beer is the equivalent of £1.44 for a 500ml bottle so exactly sale of the century. And for those that were wondering it seems it was being discontinued.

There'll be more on this later
As to the beer, it was fine. It had that unpleasant vegetal note you get in lager, but as that's generally expected I'm not complaining. I foolishly drank it after an American IPA though so any subtleties, and most of the dry hopping were lost on me.

Monday, 24 April 2017

A craft beer conundrum

There's a right lot of idealistic twaddle written about craft beer. I've been trying to get together a post about the need for a proper materialist analysis but it's been hard work so it may never appear.

Not having got my thought fully in order I was unsure what line to take on the craft beer conundrum I spied on a recent visit to Tescos. What am I to make of Adnams dry hopped lager going for 96p a can?

Is it:
  1. An abomination that Tescos are devaluing craft beer by selling it cheaply?
  2. An abomination that Adnams, a company that makes cask bitter, is devaluing craft beer by selling beer in small cans that cheaply?
  3. A bargain. 
Help bring about a better understanding of craft beer by voting in my handy poll.

Friday, 14 April 2017

A visit to Pope's Yard brewery

When I was organising trips to for the Brewery History Society this year I was keen to include Pope's Yard in Watford. It's not an old brewery, but I know they have an interest in old beers. One of the beauties of beer is that although a brewery might be long closed it is possible for its beer to live again. Or at least something close to it.

I've had a few goes at reviving old beers, and experimenting with how old beers might have been. One thing I have in common with Pope's Yard is that we've both had a go at reviving Benskin's Colne Spring Ale, though they've done a much better job of it than me.


There's a shrine to Benskins at one end of the brewery, complete with bottles of Colne Spring Ale...


... and the Journal of the Brewery History Society


The Business end of the brewery is a small German kit...


...with a smaller pilot plant for good measure:



My researches into Colne Spring Ale involved emailing a few libraries and collections which was sadly fruitless, so I based my version on an analysis Ron posted. Geoff at Pope's Yard did considerably better by physically looking through old records. Amongst some documents on brewery properties he found the Rosetta stone of Benskins: a booklet detailing how their beers were made.


As well as the historical and experimental beers Pope's Yard do make some more 'normal' ones too, which is just as well as I had a long day. All of their beers were enjoyable to drink, and I found them interesting too. A lot of the 'innovation' in breweries at the moment looks like arbitrarily throwing in a new ingredient or following the latest fad which doesn't really interest me. But at Pope's Yard you can see they're exploring where their curiosity leads them to create a fascinating range of beers.

Geoff and Ben were excellent hosts and I look forward to seeing where Geoff's recent research into ancient Sumeria via Burma takes his brewing.

Friday, 7 April 2017

The Science of Beer

Last month I did my bit for British Science Week by giving a talk on malting at the Youngs brewery in London. Well, sort of the Youngs brewery as it must be ten years since it closed, but it was on that site and there was beer from the Ram brewery there.



I was particularly pleased about that last point, as though I did visit the Ram brewery once for a SIBA event I didn't manage to get any of the beer. It was good stuff too, with that nice tongue coating bitterness.



A series of speakers was lined up, which started with Steve Livens, who at one point was a microbiologist at Youngs, though he's now at the BBPA where he spends his time trying to destroy craft beer at the behest of his evil multinational overlords, amongst other things.



His talk stated by going back 10,000 years to the earliest history of beer, and took us up to the present day and the nutritional benefits of beer.

Next was Charlie the head brewer at Wimbledon brewery, who took us through the brewing process and the materials involved.


John Hatch then gave a fascinating talk about Youngs brewery...

I'll forgive him for not doing his lab coat up, we were in a bar
... which included this fascinating slide:


What do you see there? That's right Farnham bells! I thought this was exciting until on the way to the toilet I saw the actual hop pockets themselves:


Sadly two of these hop farms have gone, but the Hampton Estate is not only still growing hops, it has recently expanded production. Intriguingly though it now only uses one bell on its hop pockets.

I was on after an interval, which was perhaps for the best as it gave more people more time to pour beer down their throats before my scientific onslaught. As I'd been asked to talk at a science event I'd been pretty merciless in cramming the detail in to my talk. Steeping, kilning, germination, Maillard reactions, that sort of thing. I don't know if it's quite what the audience were after, but I felt I'd done my bit for science.

I was followed by Craig who took us through his experiences of home brewing, and the difficulties in getting it right. 


He's now adopted a feedback system based on his experiences as a computer programmer, which didn't sound a million miles from the Deming cycle.

Lastly we had a poet, who moved things back to history and his plan to recreate a Youngs brewery dinner based on an old photograph of a staff event.


Then it was time for a quick pint or two of networking before heading home.







Wednesday, 22 March 2017

Why can't I get just one kiss?

I recently gave a talk on Brettanomyces and sour beers at work, included in which was a brief overview of sour and Bretty beer styles. Explaining what gose was lead to me getting some horrified looks. Does sour and salty beer, often with added fruit, sound unappealing I wondered? So I had to get some for my colleagues to try. I went home via Dorking that night and called in at Cobbett's Real Ales to pick up a can of Magic Rock Salty Kiss, a beer I must confess I hadn't been taken with when I first tried it. As is usually the case with me the drinking though, this was purely for research purposes so whether I enjoyed it or not was irrelevant.

I split the can between six of us, and no sooner had a started pouring than people were asking "is it meant to be cloudy?". "Yes, it's craft beer" I replied. But was that a touch of snark creeping into my voice? I do find the thought of  ahistorical historical beers slightly grating. And I've a sneaking suspicion that a beer called Salty Kiss is a prime candidate for public shaming on Pump Clip Parade. So I summoned up my best scientific objectivity and resolved to act in an unbiased and professional manner. I was somewhat lost for words when the next question was "is it meant to have floaters?". Haze can be perfectly acceptable in some styles of beer, wheat beers included*. Floaters though? Noticeable dark bits bobbing round in the beer? Surely that has to be considered a fault. So I just muttered again "yes, it's craft beer" and pressed on.


The reaction to the tasting wasn't great, and despite the small amount of beer I'd put in each glass three weren't finished.  



But on the other hand, three were. One of my colleagues said he could see if being a refreshing beer on a hot day, though thought the salty after taste detracted from this slightly. As for myself, I actually noticed a lot less salt than last time, and emptied my glass quite easily. I really need to try it on a hot day next, maybe I'll get why people like it then.







*Though I'm not sure if is Salty Kiss is a wheat beer, it wasn't listed on the ingredients but was listed as an allergen.