mashematics... Hops, Grain, Yeast

Oxygen its what we breath, our most basic sustenance, yeast feels the same way. The best brewers oxygenate their cooled worts as a matter of course

However it can be and is not good for our beer in other processes everything your grain should as fresh as possible but by by fresh thats up to at least two years old and 4 years or longer if stored cool and dry. For this we can thank Acsorbic Acid Oxydase which not only keeps our grain fresh along with other compounds but slows the oxidation of polyphenols and thiols in the mash.

However as soon as your grain is cracked oxygen starts it’s nasty work and gets to the AAO. A window of 15 minutes from crack to mash is considered safe.

The water that we pour is about 8ppm and at mash temperatures about 4ppm which is a significant amount of oxygen. We need to deaerate our mash water, the easiest way is boil and quickly cool to strike temperature (water absorbs oxygen from the atmoshere at 1-2 ppm per hour).

The grain should be added dry and the strike water under-let for least possible oxygen uptake, but it will happen during the course of the mash so to the mash sparge water add 30ppm potassium metabisulphite, this should be about right as we want to knock out any oxygen that finds, usually through agitation, its way in. It is also helpfull to add Brew Tan B at 1.5g per 20 litres of mash sparge water.  The gallotannins in BrewTan B react with wort proteins and is highly effective at coagulating proline and thiol containing proteins which are involved in lipid and protein oxidation.

If you are recirculating then keep the outlet well under the top of the mash and also be very scared of how you sparge, and if you do use the drain out of the pipe method keep the bottom of the pipe just under the drained wort level by using a pulley attachment.

These products are readily available from Mashematics

Much is written about mill gap, some from highly reliable sources and others, well its the internet !

From a small scale brewing point the most importants factors are minimal flour , maximum whole husk and lots of grits, so it is always a god idea to to have a look at the crack after the few first few hundred grams.

We sell mainly Gladfield New Zealand malts. These grains are very plump and very friable. If you are used to using less friable and slimmer grains you almost certainly have your mill gap too small for the best efficiency with Gladfields.

Here is what Gladfields have to say:

Mill gap. In this blog, I would like to draw your attention to your grain mill.

Your mill is the most important equipment you have in your brewery, without it, you could not start your brewing day.

How many of you spare a thought of your mill dying on you on a brew day? Pretty serious aye! Your mill doesn’t need to be fancy, flash or very powerful. To be honest, the most important thing about your mill is the roller gap size.

If the gap is too wide, you will under crush your malts resulting in poor yield per kilo of malt to litres of beer. If you have it too tight you will have issues with off flavours because you have trashed the husk and the most painful part of having your mill gap too tight is that you will have higher chance to have a stuck mash.

No one wants to spend longer then it is needed to brew a beer, so you all have to agree the mill gap is quite important.

Gladfield Malts are consistent in size. We screen our malts on a 2.5 mm screens which not many maltings around the world do. Most maltings de-culm the malts but not screen it. Hence our malts are free of dust, sticks and small grains.

New Zeland is famous for its plumpness which helps. If you brew with Gladfield Malts you will see consistency in grain size, if you lock your mill to the ultimum gap size you don’t need to alter from brew to brew, your welcome!

I measured our pilot brewery’s 2 roller mill now you have a size to go by.

The measured gap is 1.45 mm. We have set our mill to reflect our malts plumpness and never had any issues with runoffs or stuck mashes.

Below is our blurb about malt crush:

Our malts are both plumper and more friable. If the malt mill roller is too tight, Gladfield’s malt will be more likely to shatter and create too much flour. Consequently, brewers could experience stuck mashes. We recommend checking the malt crush before brewing with our malts for the first time. For the ideal malt crush look for the following:

• Husk – 20%
• Coarse Grits – 35%
• Fine Grits – 35%
• Flour – 10%

The average size of our malt grain is >2.8mm for barley and wheat.

Hops are only harvested once a year per hemisphere. This requires that hops are packed and stored in conditions that optimise that just pelleted quality. The Northern harvest happens about now but we do not start receiving hops here to typically late March (apart from some urgent airfreight varieties). Clearly the suppliers want to move move most the previous years first and the simple fact is that well stored they as perfectly fresh as the incoming.

What is well packed and what is well stored and how long will hops last before they start to noticeably degrade, well clearly that depends on the packing and storage. Hops are not unusual in that the big killer is air, and specifically oxygen.

Most importantly then the hops need to avoid air, ideally this is vacuum packing, they need to be kept cold (freezing is not required but may not hurt) and away from light. The worst possible storage is in clear plastic bags, which have a high oxygen permeability, outside the fridge and in the light. Clear bags (such as oxygen barrier bags that have been vac sealed and kept in the dark) are fine, this very handy if you are repacking on household vac-sealer.

There is a measure, that goes back to the 70’s called Hop Storage Index (HSI). This the amount of alpha acid acid loss after 6 months at 25C. Not much use us really !!

Here is a link to a Czech paper on hop storage, they conclude “Each component of hops has its specific value in beer brewing. These experiments have shown that the only safe way to preserve bitter acids is to store the hop pellets in a chilled space without air access.” https://onlinelibrary.wiley.com/doi/full/10.1002/jib.40

Correctly packed and stored your expensive dried hops will have no problem maintaining their quality over three years and probably more. Badly packed and after 6 months things start going cheesey.

There have been some great discussions and education in Canberra Brewers on Bio Transformation

Here is a nice simple one pager:

LAL-bestpractices-Biotransformation-print+bleed (1)

It is often said that Calcium is good for your bones and good for your beer. Canberra’s water @ 13 is fine Ca wise for Pils but a bit low for many styles (O Vienna @ 200 or Burton @270)

Here is a bit from (you will get a 404, mine is an old copy) http://www.rpi.edu/dept/chem-eng/Biotech-Environ/beer/water2.htm

<<Of the ions required for brewing, calcium is by far the most important. This is because of the acidifying effect that calcium has on the wort. […] A combination of the presence of calcium ions and the decrease in pH has a number of effects on the brewing process:

• The lower pH improves ß-amylase activity and thus wort fermentability and extract. The optimum pH for ß-amylase activity is about 4·7. Wort produced from liquor containing no calcium has a pH in the order of 5·8 – 6·0, compared to values in the range of 5·3 – 5·5 for worts produced from treated brewing liquor. The activity of the ß-amylase then is greatly enhanced by the addition of calcium, this enzyme increasing the production of maltose from Amylose, and thus making worts more fermentable.
• Calcium has a beneficial effect on the precipitation of wort proteins, both during mashing and during the boil.

Protein-H + Ca2+ (r) Protein-Ca ¯ + 2H+

The hydrogen ions released further reduce the pH which encourages further precipitation of proteins.

Proteins are also degraded, that is converted to simpler substances by proteolytic enzymes called proteases. These are found in the malt, and have optimum activity at pH values of about 4·5 – 5·0. The reduction in pH then caused by the presence of calcium encourages proteolysis, further reducing protein levels and increasing wort Free Amino Nitrogen levels (FAN).

FAN compounds are utilised by the yeast during fermentation for the manufacture of amino acids, and an increase in FAN levels in the wort improves the health and vigour of the yeast.

High protein levels in beers also have negative effects, making beer more difficult to fine and encouraging formation of hazes, in particular chill hazes. Product shelf life can also be adversely affected.

• Calcium ions protect the enzyme a-amylase from inhibition by heat.

a-amylase is an endo enzyme, cleaving the internal 1,4 glucosidic links of amylopectin resulting in a rapid reduction in wort viscosity. The optimum temperature range for

a-amylase activity is 65°C – 68°C, but the enzyme is rapidly destroyed at these temperatures. Calcium stabilises a-amylase to 70 – 75°C.

It can be seen then that the presence of calcium has positive effects on the activity of a-amylase, ß-amylase and Proteases, some of the most important enzymes in the brewing process.

• The drop in pH encouraged by Calcium ions in the mash and copper helps afford the wort and subsequent beer produced a greater resistance to microbiological infection.
• The reduced pH of the sparge liquor reduces extraction of undesirable silicates, tannins and polyphenols from the mash bed. The extraction of such materials is encouraged by alkaline sparge liquor. These materials are very undesirable, contributing to harsh flavours, hazes in the finished beer and decreased beer stability.
• Calcium precipitates oxalates as insoluble calcium oxalate.

This again occurs in both the mash tun and the copper. If oxalates are not removed they can cause hazes in finished beers and also contribute to the formation of beerstone in FV’s, CT’s and casks. Oxalates are also thought to promote gushing in certain beers, although this is not generally a problem to the micro brewer.>>

Generally speaking you will use Calcium Chloride for maltier beers and Calcium Sulphate for hoppier beers or ideally a combination of the two.

More to come

Brut IPA seems to be the current Wunderkid and I thinks makes a nice balance with the slightly older kid on the block NEIPA. I have only tasted one commercial example and no home brewed though I intend to make “Trotskys End” in a few weeks.

The use of enzymes in beer is nothing new, were it not for enzymes we would not have beer. Large commercial operations use added enzymes to make..shudder at the thought..Lo-carb beers…

So if you want to try to replicate here is a fact sheet

Mashematics will be stocking Glucoamylase. Keep an eye out.

Alcohol does strange things.

One of those means that the ABV calculated by good old simple OG-FG * x is pretty good up to about 6% ABV when the results start to drift. This is not new and was observed by Daniels in his classic Brewing Great Beers. Having brewed a RIS with some pretty stupid gravities I found calculating using this method was the better path.

So here it is (the first of a number of online calculators)