Calcium

Calcium is essential to every step in the brewing process. Most water supplies used in brewing are deficient in calcium and additions of salts are required to increase calcium to a more suitable level. The main actions of calcium are:

• It influences mash pH in a beneficial way, ensuring that the pH is kept low enough for effective mashing. This is achieved through interaction of calcium with carbonates in the water. Carbonates tend to increase wort pH, dragging it away from the optimal pH of around 5.2. Calcium binds to carbonates forming compounds that precipitate out of solution and remove the ability of carbonates to influence mash pH.

• Calcium protects malt amylases against heat inactivation during the mash. Malt amylases steadily lose their ability to convert starch into simpler sugars during the mash because the mash temperature is a compromise between the optimal operating temperature of both alpha and beta amylase. Alpha amylase suffers most during the mash, but a sufficient calcium concentration protects the enzyme from heat inactivation.

• During the boil trub is formed by the precipitation of protein matter through thermal degradation, but calcium plays a significant role in trub formation by neutralising protein molecules through electrostatic interactions. A minimum calcium concentration of 100 mg/l is required for good trub formation.

• Yeast flocculation is aided by calcium through the interaction with proteins on yeast cell walls. Most strains require at least 50 milligrams/litre (mg/l) for good flocculation.

• Beer stone is formed from a build up of oxalate on brewing equipment. Oxalate in packaged beer provided nucleation sites for carbon dioxide that promotes gushing upon opening of the package. Values of 70 - 80 mg/l are sufficient to remove excess oxalate from the brewing process.

When making calcium additions it is important to account for the significant amount of calcium that is retained in the grain during mashing. The calcium that ensures effective mash pH is sacrificed during the acidification process in the form of calcium carbonate, a solid that precipitates and sticks to the grain. This loss can account of or 50 - 60% of the calcium in the mash.

Increasing calcium values to 200 mg/l has shown to increase run off from the mash tun, improve extraction and also increase free amino nitrogen - an essential nutrient for yeast. As the the wort gravity decreases during run off the pH tends to increase, promoting the undesirable extraction of tannins and silica from malt husks. However, it has been noted that increasing calcium in sparge water to 200 mg/l can prevent the wort pH increasing and reduces the extraction undesirable compounds.

The amount of calcium in your brewing water can be measured using test kits that are commonly used for aquarium water analysis. However, it can be assumed that most brewing water does not a have the 100 - 150 mg/l calcium that is desired for brewing. Below are some simple calculations for making calcium additions using minerals commonly used in brewing.

• The water will have a some calcium already present, though it will very likely be sub-optimal. When calculating the amount of calcium to add, the quantity of calcium in the water already must be subtracted. So that's the first step.

• This value is then divided by the percentage of calcium present in the salt you have decided to add. This value differs depending on the salt used and the extent to which water is bonded to it. Calcium sulphate has the chemical formula CaSO₄.2H₂O. A bit of chemistry tells us that calcium accounts for 23% of this molecule, so the value of calcium in mg/l that we want to add is divided by 0.23.

• This value is then multiplied by the litres of water that you want to treat.

The most common calcium additions in brewing water come from the following salts:

Calcium sulphate: CaSO₄.2H₂O - 23% of which is calcium

Calcium chloride: CaCl₂.

Calcium chloride is very hygroscopic, which means it readily absorbs water from the atmosphere. As a result it is found in a number of forms. This influences the amount of the salt that must be added. If the molecule has two water molecules attached calcium makes up 27% of the molecule, but if has seven water molecules attached calcium makes up only 18% of the molecule. That means our numbers in the calculations in step two are 0.27 and 0.18 respectively.

An example might help clarify this:

Take some tap water with a calcium concentration of 60 mg/l. Let's say we boost the calcium to a more respectable 150mg/l, and we're brewing a stout so we should use calcium chloride to add some body.

There's 60mg/l calcium in the water already, this means we need an additional 90 mg/l to meet our desired value of 150 mg/l. Calcium chloride takes up water readily so we'll assume that your supply of calcium chloride is fully saturated with water thanks to the shoddy way you store it. This means you have:

CaCl₂.7H₂O - 18% of which is calcium.

You want to add 90mg/l:

90/0.18 = 500 mg/l

You have, say, 30 litres of water to treat, so:

500mg/l x 30l = 15000 mg = 15 grams of calcium chloride in 30 litres.

The scenario is the same for the addition of calcium sulphate to water used to brew a crisply hopped pale ale.

We need to add, say, 100 mg/l calcium so,

100/0.23 = 435 mg/l

And we need to treat 40 litres of water:

435 x 40 = 17391 mg = 17.4 grams of calcium sulphate in 40 litres.

As can be seen, it is easy to boost the calcium levels in brewing water, but it is important to consider that in each of the examples above addition of chloride and sulphate were also made to the water, which might result in a unsuitable balance of each of these constituents. A blend of both can help too much of either dominating, while ensuring that calcium levels are met.

Dark beer and dark evenings, all fit for writing

The Beer Nut's musings on the joys of 'having written' gave me much to think about yesterday. I agree with him entirely, particularly about the joys to be had from a disciplined approach to writing. Sadly, I don't feel as disciplined as perhaps I should be, and my rigidity of thought with respect to how important it is to be disciplined and my apparent lack of it, is a source of consternation to me. I mean, take a look at Ron, he's a blogging machine, driven by what precisely I don't know, but you know he just loves it. Not just the having written aspect but the process of cramming all those facts and anecdotes into his posts. Mark Dredge is similarly prolific, but he just wants to write, it is essential to his well being and his beer blogging is a means of combining two things he enjoys. If you query The Beer Nut about why he blogs, he'll give you a glib answer along the lines of the need to document the beer he drinks, but it's clear there is far from mere ticking at work on his pages - you just don't have to write that well to make a list of conquests. The beer community is the better for it.

I'm glancing to my back garden while I painfully hammer out these words. Things are starting to stir. The tail end of hurricane Bill is heading this way, the depression slowly moving eastward across the country, promising heavy rainfall and a night of blustery mayhem that will no doubt slaughter the impressive sun flowers my wife has tended to over the summer. Much like other beer lovers, on evenings like this my mind turns to dark beers, particularly stout.

I am shameless in my promotion of American dark beers, but I feel this enthusiasm is entirely justified by the shear quality of those I have tried. The uncompromising nature of American brewing suits stout particularly well, mainly because flavour is packed into them but not in an overpowering one dimensional hop bomb way. It's just full, rich, complex roasted goodness with the occasion always just right measure of hops. The strong pedigree that this Oatmeal Stout traces its family tree from whet my taste buds from the off - Goose Island's IPA is a world beater, and the stout delivers in a similar manner. It's a cliché to say that an oatmeal stout is smooth, that's the very reason the oats are added, but this one really is. This may well be as much to do with the perfect carbonation as anything else. The one thing I didn't expect, but welcomed greatly was the quite pronounced smoky, phenolic note on the nose, very similar to Islay scotch. The smoke didn't follow through onto the palate, instead was replaced with wonderful bitter chocolate, coffee and a long lingering bitterness. I'm not surprised really, the damn label even looks tasty, and is the most striking manifestation of Goose Island packaging I have seen.

I feel much better now, having written.

Berliner Weisse for kids?

This bottle of Berliner Kindl Weisse has hung around in my fridge for quite some time now. I didn't worry about it going bad, the lactic acid content took care of any spoilage issues, but also the right moment to drink it just didn't present itself. It is a style of beer I've been eager to try for quite some time with the promise of a sharp tang and low alcohol content. Sadly this brand of Berliner weisse left me a tad unsatisfied.

What little I now about Berliner Weisse is this:

• Low abv (2.5 - 3.5%)
• Very low IBUs (3-8), no aroma hops are added, and often the beer isn't even boiled, with the hops added during the mash.
• A good measure of of unmalted wheat is used in the grist.
• There should be a pronounced lactic character without any acetic notes.

Everything you need to know about this history of this beer can be found at Ron's, of course. I was keen to see if it really measured up in the taste intensity stakes, like Cantillion's Lambic and I thought I was in for a treat if there is any truth in the stories about barman in Berlin looking at you curiously if you don't drink the stuff "mit schuss", the idea being that it is intolerable without some syrup to ease the palate somewhat. From the off I was determined to drink it without any flavour additions but need not have worried as this particular Berliner weisse is very tame indeed - almost to the point of a slightly sickly blandness. The lactic character is there alright, but it doesn't bite and leaves a vacuum on the tongue where you might expect the pleasant acidic tingle to satisfy. The carbonation wasn't as high as anticipated either - three to four volumes of CO2 are common, but the malt was reasonably with a grainy/bready contribution.

This lack of flavour and intensity has led me to believe that I have got a form of Berliner Weisse Lite on my hands. The cheeky sprog on the label makes this seem even more likely. Perhaps Barry can shed some light on this beer from his newly adopted home in Germany?

I knew I'd regret it

I feel as if things have been busy lately. Perhaps they have, but I still can't justify the degree of neglect this blog has received. My laziness came back to haunt me again earlier this week when I decided to stuff my Cobweb Ale into a Cornelius keg that was in no way ready to hold it. I bought the kegs a few months ago, but owing to lack of space I have yet to get a fridge to put them in or any gas to run them. But that didn't stop lazy old me from racking 18 litres of ale into one. It was part laziness - the thought of preparing and sanitising sufficient bottles horrified me - but also I thought I had found a way around the gas problem by buying some small 16 gram CO2 cartridges that I could prime the keg with. I knew I would run into trouble but it didn't stop me because the beer had sat on a bed of dead yeast for far too long and a move had to be made.

So I whacked the ale in the keg along with some finings and priming sugar just before I set off on holiday for a week, and returned to find the keg nicely pressurised but not at all bright and tasting kind of sharp. I think the beer was off before it went in the keg, but it became clear that any chance I had of properly carbonating it was ruined after a glimpse at the gas pressure tables told me that at the ambient 20 C the beer was sitting, a pressure of around 24 pounds per square inch is required to get sufficient gas into the beer. That's higher than the keg is rated for, I think.

A fridge is definitely in the pipe line.

Kilkenny City: Epic Beer Fail.

Well what do you expect from a small town with a Diageo run brewery sitting at its very heart? It's called a city for some reason. I ran through the various explanations I had heard for this designation; a cathedral, a castle, sufficient population, but in the end you can't help but come to the conclusion that it is a town, and a delightful one at that. It has a distinct medieval feel, mainly from the large amount of old rock and stones about the place. There are plenty of cobbled streets and ancient walls, as well as the castle, of course which sits on the river Nore and has no doubt seen a fair bit of action over the years, what with the bellicose nature of the natives.

Diageo's St Francis Abbey Brewery was closed last Saturday when I dropped into town with my wife to quietly celebrate my 30th birthday. I had nosey around the outside of the of the brewery, but nothing of interest was going on despite Diageo's claim that Budweiser is brewed 7 days a week on the premises to satisfy the seemingly unquenchable Irish thirst for this uninspiring beer.

Kilkenny is a town of pubs and churches (much like many Irish towns), but the quality of them is very high. The beer in the pubs sadly is not; the usual fare of Budwesier, Guinness, Smithwick's, Carlsberg and Heineken. I couldn't help but try some Kilkenny Irish Ale while there because it was one of the first beers I tried all those years ago. It was a go to beer for me around a decade ago when it was launched, but very few drank it and it was something of a gamble when ordering it in a Dublin pub. It tasted of far less than I recalled - unsurprising really because back then Kilkenny was damn near a speciality beer. Nowadays, to my more experienced palate, it tastes of damn all. The overriding flavour was nitrogen, I reckon. I also sampled some Smithwick's over the weekend, and came to the conclusion that it and Kilkenny Irish Ale are one in the same, save for the nitrogen adulterant.

The weekend wasn't a complete beer wash out, mind. Thanks to Laura I found The Wine Centre, a blissful oasis in this beer desert. When I walked in two guys behind the counter were discussing the merits of Fuller's ESB. My kind of place! It contains a very respectable selection of world beer, more than enough to keep the average beer geek content, and well worth visiting if you're in town. Laura alerted me to The Wine Centre after I had arrived in town, but fearing things would be a little barren on the beer front I brought a few bottles from home to stock the mini bar and aid my comfort while in the hotel. These included some Zeitgeist from Brewdog, and a bottle of Fuller's Summer Ale. I can't recommend the Summer Ale at all; it disappoints in so many ways, but Zeitgeist proved to be top notch, full of roasted malt and very clean. But it can't replace Brooklyn Lager, despite what some Irish Twitterers have suggested.