Mash PH

[illywhacker]

i preheat the tun and don't get any sort of temp drop in the hour, but i'll try a stir every fifteen next brew, check it out.

hell, at 50% efficiency, i can't get much lower!

recirculating should help somewhat it seems.

anything else obvious i may be missing?

[chris.]

i preheat the tun and don't get any sort of temp drop in the hour, but i'll try a stir every fifteen next brew, check it out.

hell, at 50% efficiency, i can't get much lower!

recirculating should help somewhat it seems.

anything else obvious i may be missing?

Can you give us some more info illywhacker?
How much grain & water are you using?
Batch sparge or fly sparging?
Can you give us a run down on your process?

Cheers

[illywhacker]

Can you give us a run down on your process?
Cheers

fair call.

i've only done one ag to date, so i'm still very green

i use 2 x cylindrical eskies. one max 15L with a stainless steel braid manifold, the other 7L w/ grain bag.
i had been using the latter for partials and added the former to go ag at minimal extra cost.

i used 5.6kg grain for a 20L brew as i had been getting pretty poor efficiency in my partials. divided the grain in proportion with the tuns' capacity.

used 2.5L mash water per Kg grain for both mash and 1 x sparge. this did leave me under my target amount wort amount, so hopefully sparging with mare water will improve my efficiency somewhat.

found this webpage which was extremely helpful in that regard.
http://www.allaboutbeer.com/homebrew/water.html

both mash and sparge were bang on 66*. left mash for a little over 1 hr without touching. found temp to be pretty much 66* after the hour.

when lautering, i drained run-off straight to kettle.
in the small tun, i rotated the grain bag to try to stop sugar extraction from only the grain around the tap. this is obviously not ideal, and am thinking of fixing up a small manifold for this tun also.

og was 1.043

hope this helps you help me

thanks

[BierMeister]

Provided you have pre-heated your mash tun? Otherwise you'll have cold spots towards the sides, and especially near the corners. Also if your mash tun is less than perfect at insulating then the whole thing will slowly drift downward.

I generally do pre-heat my tun. But again this is not essential.
What are you mashing in rwh? anything insulated should not have any problems.
Could it be that the slow drift downwards is due to taking the lid off every 15mins (to stir) & as a consequence your letting heat escape?

What mash tun is perfect? I have a sneaky suspicion that I lose more heat by checking and stiring every 15 or so than the esky is losing heat. I'll be cutting it back to every 30 from now on, unless I'm decocting and then you have to check every 30 or so anyway. Either way, at the moment I lose 1-2 degrees over 90 mins which won't effect the end result all that much, surely?

[beerdrinker]

Just did my fourth AG (a german lager) and have a miserable 65% efficiency. My pH seems to always be under 5 I used pH5.2 this time but still had a mash pH of4.8. Can anyone help on the pH issue? cheers. tastes and smells awesome

[Kevnlis]

Short of water chemistry... you could try some acid malt but it does leave a bit of a sour taste.

[Trough Lolly]

Just did my fourth AG (a german lager) and have a miserable 65% efficiency. My pH seems to always be under 5 I used pH5.2 this time but still had a mash pH of4.8. Can anyone help on the pH issue? cheers. tastes and smells awesome

G'day Beerdrinker,
What's your water source? Tap....tank....toilet?!

Cheers,
TL

[beerdrinker]

Usually carbon filtered sydney water from prospect. Latest batch was half RO half tap. cheers TL

[Kevnlis]

If you are using half RO water and half charcoal filtered tap water you possibly do not have enough salts in the water for the mash to reach the appropriate pH. Get yourself a pH metre it is well worth the investment! Also have a read on Palmers water chemistry section, it explains why this happens:

http://www.howtobrew.com/section3/chapter15.html

Further, do you have a water softener in your home?

[Trough Lolly]

Usually carbon filtered sydney water from prospect. Latest batch was half RO half tap. cheers TL

No probs - given that you can already measure the pH of the mash strike water, I'd add one teaspoon of Bicarb of Soda that you can get from the Supermarkets to push up the pH before dough-in.
Just keep an eye on your pH - add small amounts of salts to avoid overdoing the pH adjustments.
Cheers,
TL

[beerdrinker]

Hi Kev, no water softener just the Carbon filter. Might add the bicarb as TL suggested

[Kevnlis]

The problem I see with that is, if salts would that simply fix the problem, the pH5.2 should be working.

Have you tested the pH before you have added the grist? Try to add a bit of bicarb and then retest the ph, see if it changes. Also when you add the pH5.2 retestet to see if it has an impact.

[beerdrinker]

The pH of the strike water was 7.1 before adding the 5.2. After adding the 5.2 the pH reading was 5.1 then the mash ended up at 4.8. ive been using one of craftbrewers digital pH meters. My unfiltered tap water is 7.5 while the carbon filtered water is 7.1?

[Trough Lolly]

The problem I see with that is, if salts would that simply fix the problem, the pH5.2 should be working.

Have you tested the pH before you have added the grist? Try to add a bit of bicarb and then retest the ph, see if it changes. Also when you add the pH5.2 retestet to see if it has an impact.

Can't argue with your logic Kev, but I think the problem is buffering...I don't think his water has much in the way of permanent hardness...

Cheers,
TL

[Kevnlis]

The problem I see with that is, if salts would that simply fix the problem, the pH5.2 should be working.

Have you tested the pH before you have added the grist? Try to add a bit of bicarb and then retest the ph, see if it changes. Also when you add the pH5.2 retestet to see if it has an impact.

Can't argue with your logic Kev, but I think the problem is buffering...I don't think his water has much in the way of permanent hardness...

Cheers,
TL

That is exactly my point TL, adding more salts will not fix the problem IMHO. I am no chemist, or water expert so take my comments with a grain of salt (pun intended )

[beerdrinker]

Broke my pH meter testing water samples was experimenting adding sodabicarb and the glass bulb broke going to get the one from craftbrewer that accepts new probes

[Trough Lolly]

The problem I see with that is, if salts would that simply fix the problem, the pH5.2 should be working.

Have you tested the pH before you have added the grist? Try to add a bit of bicarb and then retest the ph, see if it changes. Also when you add the pH5.2 retestet to see if it has an impact.

Can't argue with your logic Kev, but I think the problem is buffering...I don't think his water has much in the way of permanent hardness...

Cheers,
TL

That is exactly my point TL, adding more salts will not fix the problem IMHO. I am no chemist, or water expert so take my comments with a grain of salt (pun intended )

Ok, at the risk of going overboard (what the hell, it's raining outside and I'm nursing a hangover so I might as well do something useful online!)....

\\ Beer Geek mode on! //
Palmer kicks off proceedings in a general manner, at Chapter 15:

The term "hardness" refers to the amount of calcium and magnesium ions in the water. Hard water commonly causes scale on pipes. Water hardness is balanced to a large degree by water alkalinity. Alkaline water is high in bicarbonates. Water that has high alkalinity causes the mash pH to be higher than it would be normally. Using dark roasted malts in the mash can balance alkaline water to achieve the proper mash pH, and this concept will be explored later in this chapter.

So let's explore a bit deeper - there are various types of water hardness. Two that are often referred to are general hardness (GH) and carbonate hardness (KH). GH + KH = Total Hardness, but I don't often refer to total hardness since it can potentially be misleading as we're often more interested in the GH and KH components rather than the aggregation.

GH primarily deals with the concentration of calcium (Ca++) and magnesium (Mg++) ions that are present in water (there are other ions, of course, but their contribution to GH is relatively insignificant for this discussion). So, harking back to our Chemistry classes (?!) GH is expressed as: parts per million (ppm) of calcium carbonate (CaCO3), degrees hardness (dH) or more accurately, the molar concentration of CaCO3...and for a benchmark, a molar concentration of 1 milliequivalent per litre (mEq/l) equals 2.8 degrees hardness (dH) equals 50 parts per million (ppm).

0 - 4 dH, 0 - 70 ppm : very soft
4 - 8 dH, 70 - 140 ppm : soft
8 - 12 dH, 140 - 210 ppm : medium hard
12 - 18 dH, 210 - 320 ppm : fairly hard
18 - 30 dH, 320 - 530 ppm : hard

We also need to note that whilst hardness is equivalent to how much CaCO3 is in the water, we need to remember that the hardness does not mean that CaCO3 is the sole source of hardness - it can come from a number of salts as we know in Palmer's book...ok, let's get back on topic!!

Carbonate hardness (KH) measures the bicarbonate (HCO3-) and carbonate (CO3--) ions present in the water. It's often referred to as a chemical buffer that helps to keep the pH stable.
For our mashtuns we need to look at the presence of bicarbonate ions for our neutral pH. pH is basically determined by the negative log of hydrogen ions (H+) in the water.

pH = pK + log (base/acid) or pH = 6.37 + log(HCO3-/H2CO3)

If you toss in an acid such as nitric acid, it breaks down into hydrogen ions and a nitrate salt - the additional hydrogen ions now present in the water will reduce the pH (it's a negative log, remember). If we have carbonate buffering in the water, the bicarbonate ions will combine with these extra hydrogen ions and form carbonic acid (H2CO3) which eventually dissipates out as CO2 and water (magic, ain't it!!). If you want to know what carbonic acid tastes like, try gassing up a keg of water - or trust me when I tell you that it's very bitter and not worth wasting your bottle of CO2 over!

So, we've got bicarbonate ions joining the excess hydrogen ions, making carbonic acid in the process. Now we're robbing the bicarb ions in solution to do this, so our buffering ability will fall and that means that the pH of the water will eventually swing about wildly since the buffer is being used up. Water with a low level of carbonate hardness (KH) will be quite pH unstable. As we add acidic / dark grains to the mashtun, you will see the pH fall quite quickly as the additional hydrogen ions aren't "mopped up" by the buffering bicarb ions...

Now, how to fix things...Well, we know that General Hardness is a measure of calcium and magnesium. We can use calcium sulphate (CaSO4; aka food grade Gypsum), or magnesium sulphate (MgSO4; aka Epsom Salts) to sort out the GH, but remember, we are adding sulphates as a result so you need to be easy on the additions otherwise you're possibly doing more harm to the strike water, than good. Sulphates do contribute to hop "crispness" as Palmer suggests, but they can also er, stir up the lower digestive system if you have too much of a good thing! If you already have a high sulphate level in your water, I'd add calcium via Calcium Chloride instead, but only if your water has a low chloride count! See, it isn't easy to do make these adjustments without a decent water report...You need a starting point in order to work out which salt is the best one to use, if at all.

We can increase the carbonate hardness (KH) with sodium bicarbonate (NaHCO3), which yes, adds sodium as well, so be careful with your additions. Calcium carbonate (CaCO3; aka chalk) also does a good job, by increasing both KH and GH in equal proportions but it isn't the easiest thing to dissolve in your mashtun. Adding bicarbonate ions will increase the base to acid ratio (see the equations above) which means the pH will increase.

Now without going into another essay, we also need to bear in mind that some hardness salts are alkaline based and some are not. Why is that important?
Well, alkaline based hardness salts such as carbonate and bicarbonates of calcium and magnesium (that we used to address General Hardness / GH) are only temporary hardness salts since they can be decomposed by boiling the water - which we often do when we brew a batch. The boil releases the CO2 and leaves the carbonates behind - often in the form of scale deposits in the brew kettle.
Non alkaline based hardness salts such as the chlorides and sulphates of calcium and magnesium are referred to as permanent hardness salts and they cannot be removed by boiling the water. Texts define Total Hardness as the sum of alkaline and non-alkaline salts present but to me that's only part of the story...
Anyway, sorry for the rambling post, but I hope it sheds some light on this topic - and to be honest, it's not essential that we put on a lab coat and go berserk with brewing salts to make a decent brew - it's just part of the overall brewing process.
\\ Beer Geek mode ends! //

Cheers,
TL

[munkee]

shouldnt we be worrying more about simply matching the beer style with the mineral profile in your available water ?

where I come from the water is super soft, but highly alkaline. That of course means very low salts, but sufficient hydroxide ions to take the pH > 8. They do this to prevent corrosion in distribution pipework. Because its so soft only a minute quantity of organic acid is required to bring the pH to strike target, but this is questionable because of the huge buffering power of the mash itself.

if you have super hard water, brew a good dark ale. If you are super soft, you have to add salts to achieve the style you want.

in my experience, adjust the salts to match your style profile and the mash pH will take care of itself...

[Trough Lolly]

Wise words, Munkee...I too have soft water here in Canberra and that's great for APA's and my pale lagers - when I want to brew something a bit darker, it's easy to toss a bit of Gypsum in, if I bother at all.

Cheers,
TL

[beerdrinker]

Are you a scientist TL? nice post Am thinking of using rainwater instead of my sydney toilet water,should i add salts for light beers? cheers