Partial mash,1st attempt.

[mark_68]

If all goes well next sat. i will be attempting my first partial mash.I am going to use my 15 litre pot as a tun until i buy an esky.To try and keep the temps. stable i have lined a big cardboard box with polystyrene,leaving enough room for my pot and a quilt jammed into the top.I will use another 15 litre pot to heat my mash water and have made a grain bag so i can take the grain out of the first pot,letting it drain first,then put it in the other pot with water heated to 80 degrees to hopefully get a little more sugar out.The only thing i am a bit suss about is the temp. of water that beersmith calculated for me,but as it is not a huge tun i should be able to change temp. pretty easily with cold or boiling water,another 2 pots!! To work out how much grain to use i set beersmiths efficiency at 55%,probably still optimistic but i had to start somewhere.Hopefully it all comes together,we will see.
RECIPE:
500 gms dark dry malt,340 gms wheat malt,1.5 kilos coopers LME,1.45 kilos ale malt,700 gms munich malt and 250 gms carapils.40 gms perle(60 mins)&30 gms tettnang(20 mins).Safale US56 or K97 if i can get it.

[Ed]

Mark, it's very easy to keep a pot that size in the right temp range. That's what I used before getting a cooler for a tun. If you miss your initial temp, you can apply heat on the stove while stirring, it doesn't take much. Also, just take the shelves out of your oven, preheat it, and then shove the tun in there with the oven switched off. It will hold the heat very well over the hour.

Cheers, Ed

[mark_68]

The oven idea certainly sounds good Ed,thanks mate,i will use that instead of the box,it should help keep temp. higher during hour.I will pre heat it to maybe 100 degrees then switch off,does that sound about right?

[Ed]

It's about what I did Mark. Shouldn't find any probs, but just don't go too hot as the oven really retains heat.

Cheers, Ed

[Trough Lolly]

If all goes well next sat. i will be attempting my first partial mash.I am going to use my 15 litre pot as a tun until i buy an esky.To try and keep the temps. stable i have lined a big cardboard box with polystyrene,leaving enough room for my pot and a quilt jammed into the top.I will use another 15 litre pot to heat my mash water and have made a grain bag so i can take the grain out of the first pot,letting it drain first,then put it in the other pot with water heated to 80 degrees to hopefully get a little more sugar out.The only thing i am a bit suss about is the temp. of water that beersmith calculated for me,but as it is not a huge tun i should be able to change temp. pretty easily with cold or boiling water,another 2 pots!! To work out how much grain to use i set beersmiths efficiency at 55%,probably still optimistic but i had to start somewhere.Hopefully it all comes together,we will see.
RECIPE:
500 gms dark dry malt,340 gms wheat malt,1.5 kilos coopers LME,1.45 kilos ale malt,700 gms munich malt and 250 gms carapils.40 gms perle(60 mins)&30 gms tettnang(20 mins).Safale US56 or K97 if i can get it.

G'day Mark_68,
Good luck with the partial mash brewday - you should easily hit 55% efficiency if you keep an eye on mash thickness and temps.
When I partial mashed, I used to heat the water up to around 60C, add the grains and after dough-in, bring up the temp to target with the burners on the stove, stirring regularly to avoid scorching on the pot floor. There are two major benefits from doing this method:
1. Dumping grains in is a sure fire way to get dough balls which are sometimes hard to find / breakdown, and waste grains by not allowing the water to penetrate all of the grist - resulting in underconverted, hazy starch present wort. So we tend to add grains slowly and steadily, stirring as you go - or use other techniques such as underletting. The point is that grains go in slowly and that's a problem if you have 80C water. If you slowly add the grains, you risk extracting harsh astringent tannins from the grains whilst the temp of the mash water remains above 75C.
2. We are lucky enough to have well modified malt at our disposal and the bulk of the starch conversion typically occurs in the first 20 minutes of the mash. That said, I still mash for at least an hour. The point here is that the mash temp is critical in determining what enzymes will be left to convert the grains starches into sugars. If you have the mash water above 68C for the first 20 or so minutes, the hot mash will certainly denature (destroy) the cool mash temp tolerant beta-amylase enzymes, leaving hot mash temp tolerant alpha-amylase enzymes to do the conversion, which typically results in a fuller bodied, lower alcohol wort. Now, that may be fine for your particular beer style, but generally speaking, once the beta-amylase enzymes are gone, there's nothing you can do to bring them back, even if you add cold water to the mash. Of course, the opposite applies and you can have drier, thinner wort with more alcohol potentially available if you do a "cool" mash between 60 and 65C...Here's a basic pic of this concept:

Sorry for the lecture but I thought it may be helpful to bear these things in mind when you add the grains to the mashtun. With practice you can use the temperature to your advantage and fine tune the mash that makes all the difference when it comes to nailing a particular beer style that you enjoy drinking...

Cheers,
TL

[BierMeister]

The point here is that the mash temp is critical in determining what enzymes will be left to convert the grains starches into sugars. If you have the mash water above 68C for the first 20 or so minutes, the hot mash will certainly denature (destroy) the cool mash temp tolerant beta-amylase enzymes, leaving hot mash temp tolerant alpha-amylase enzymes to do the conversion, which typically results in a fuller bodied, lower alcohol wort. Now, that may be fine for your particular beer style, but generally speaking, once the beta-amylase enzymes are gone, there's nothing you can do to bring them back, even if you add cold water to the mash.

Slightly misleading I'd say. 68C-70C will not denature(destroy) the beta-amylase enzymes. They don't work efficiently at such temps but there will still be minor beta activity at this sort of temp. Just as at 62C you will get minor alpha activity. Once you start getting over 70C then yes the beta stops pretty much all together, but I wouldn't say 70C denatures beta, possibly but not all. Between 65-67C gets the ideal balance between the two.

[mark_68]

Thanks for the replies guys,i have now got an idea of what i am doing,the oven is definitely the way to go for temp. stabilisation,as far as temp. of mash is concerned i will have my initial water heated to 70 degrees and then after slowly adding the grain i will check temp. and either add some heat on the stove or add some cold water to bring the temp down a bit.Does this sound about right for this method?Another question; according to an online book iwas reading last night(Brewing:science and practice)the mash itself is isothermic,so it generates enough heat to keep the temp. pretty stable in a brewery mash tun etc.,will this still apply to a much smaller tun,such as what i am using,or does this only work with large mashes?

[Trough Lolly]

To be honest, the issue of whether the mashtun you use is capable of holding a steady mash temp, or not, is all part of the experience you get by doing plenty of mashes. I find the 10 Gallon mashtun I use is pretty stable, once it's preheat before dough-in. You may find the same and if you have the mashtun in the oven, I'd keep a very close eye on the mashtemp for the first few brew sessions...

Cheers,
TL

[mark_68]

I have been doing a few test runs with my thermometer to test how accurate it is ,so far it looks pretty good.I put 3 litres of hot water in my pot at 59 degrees and then put a cup of cold water into the pot after and it was 55 degrees,so i at least know the thing works.The only problem i have found with it so far is i have to put the probe all the way into the water as i have noticed that it gives a reading 5 to 6 degrees off if i only push it in a little way,that's what you get for 20 bucks i suppose.If this thing proves no good i will buy the more expensive digital version.The HB store bloke reckons to do an iodine test with drop of wort to see if there has been any conversion,so i will buy some betadine and use a white plate to test the wort,if it ain't converted then i will have to buy a more accurate thermo.I am also buying a new 20 litre pot this week as the cheap 15 litre pot i have got is potentially dangerous,the handles are spot welded on and could break with a full pot of hot wort in there,ouch.

[Swifty]

You can get 19L pots from Big W for about $15 from memory.

[SpillsMostOfIt]

Depending on where you are, you might be able to do better value than BigW. There are a couple of shops in Smith St (Collingwood - not that horrible Smith St in Fitzroy) that sell a lot of really cheap stuff. I saw *big* SS pots in one of them for not a lot of money.

[Swifty]

How big is "big"? I'm looking to get a bigger pot, say 40L upwards.

[SpillsMostOfIt]

For reasons that escape me, they didn't (as I recall) have their volumes, just size in cm. I reckon they had 40litres or more.

Are you local?

[Swifty]

Out Croydon way but will travel for a well priced pot. At the moment I'm doing split boils with two 19L pots which works good cause I only have an electirc stove to use but would like to get a burner and big pot.

[drsmurto]

For reasons that escape me, they didn't (as I recall) have their volumes, just size in cm. I reckon they had 40litres or more.

Are you local?

Nerdy response - Volume (of a cylinder) = (pi)r2h. If you approximate pi = 3 and 1/2 the diameter to get radius and h = height you have a very quick (mobile phones are also calculators if the maths gets a tad too much) approximation of volume.

Will go back into my lab now

DrSmurto - super nerd

[SpillsMostOfIt]

I don't have a mobile phone, you insensitive clod!

When I was looking at them, I had just purchased my FB Boiler and was mainly basking in how much money I had saved myself.

If we really need to know, I could probably wander down there and do the necessary reconnaissance... *sigh*

[Trough Lolly]

Asian foodstores often have excellent deep frying pots that they sell very cheaply - just have a good look over it and buy a pot that has nice and solid handles - dropped pots can turn your brewday into custard...

Re the Iodine test, that's an acceptable but crude way of determining conversion since the iodine colour change occurs due to the presence of starch so if you've had full conversion, the iodine solution will remain unchanged in color. Obviously, you don't return the sample to the mash and it's important to cool the sample before you test. Also note that you can get a false reading if you have accidentally got some grain husk matter caught up in the sample.

Cheers,
TL

[SpillsMostOfIt]

Out Croydon way but will travel for a well priced pot. At the moment I'm doing split boils with two 19L pots which works good cause I only have an electirc stove to use but would like to get a burner and big pot.

The thing that clinched moving off the gas stove for me was the temperature of the surrounding granite benchtops. I had instant approval to buy whatever heat source I wanted.

I recommend you do your sums carefully. Barbecue gas can get expensive in my view.


Hmmmmmm.... Custard...... *gurgle*

[Swifty]

I'm happy with my setup at the moment, it's cost me less than $100 and I can do 23L all-grain batches with up to 5 or 6 kg of grain. The electric stove would probably be very cheap in comparison too. The split boil makes it easier to move the pots aswell. I guess one of the main reasons would be to move brewday out of the house.

[mark_68]

I didn't realise you had to cool the sample first,no worries,i'll leave it sit for a few mins.The 19 litre pots from big w are the same as the pot i have at the moment,they have spotwelded handles on them which do not look safe to me.Idiot me still bought one though,so now i have to shell out more money for a decent pot with riveted handles.Esky and manifold coming soon.