Exmoor Gold Questions...

[Wez]

Im planning on brewing this one at the weekend and have some questions that you guys might be able to help with. The recipe given in BYORAAH is:

5kg Pale Malt
34g Fuggles (full boil) AA 4.5
28g Challenger (full boil) AA 7.7
20g Goldings (full boil) AA 5.3
20g Goldings (last 15) AA 5.3

23L batch
OG 1045
EBU 32

When I put these figures into beersmith using the AA ratings that Wheeler gives (shown above) the EBU comes out at 51.8 EBU (why is there such a difference does anyone know?)

I'm going to alter the recipie to a 25L brewlength and to acount for my 74% brewhouse efficiency and for the AA of my hops (which i won't know until I get them from the brewery on Saturday) and i'll target the 32 EBU's it shows in the book but i'm worried that if beermiths calc's are good then when I use this software to work out my hop qty's I might under estimate hops

[Wez]

Now i'm spun out...do I go with beersmith or wheeler or in between

[Wez]

So do you mean that when I know the AA of the hops i'm getting use the formula in byoraah to get it to match the 32ebu and ignore what beersmith comes back with. I can feel a poll coming on Beermith V's Wheeler

[Scooby]

Just to confuse matters this is from the 1998 edition

4.6kg Pale
50g challenger start
21g Fuggles start
10g Fuggles last 15mins
10g goldings last 15mins

23l
OG 1045
EBU 40

[kinnockthecat]

I put your recipe into the Beer Recipator website http://hbd.org/recipator and came up with 50 IBU which is what I'd expect from a stout or similar.

I would tend to go with Wheeler myself.

[steve_flack]

Basically Wheeler assumes a flat utilisation of 20% regardless of gravity - and to be fair most commercial brewers seem to assume a flat figure then adjust based on lab results.

The major brewing softwares can use a number of formulas to calculate utilisation. The formulas pretty much all agree that utilisation drops in stronger beers. The way they actually calculate the figure differs hugely. If anyone really cares I can post the formulas for the calculations but it is pretty dull stuff....

[Wez]

Get in on Steve

[steve_flack]

From the actual BeerAlchemy code

Code: Select all

	switch (formula)
	{
		case KPSTinsethsFormula:
		// Using Tinseth's method
		{
			float bignessFactor=1.65 * pow(0.000125,gravity - 1);
			float boilTimeFactor=(1.0-exp(-0.04*time))/4.15;
			basicUtilization=bignessFactor*boilTimeFactor;
			break;
		}
		case KPSDanielsFormula:
		// Using Daniels' method
		{
			
			float util=0.05;
			if ((time>=10) && (time<20)) util=0.12;
			if ((time>=20) && (time<30)) util=0.15;
			if ((time>=30) && (time<45)) util=0.19;
			if ((time>=45) && (time<60)) util=0.22;
			if ((time>=60) && (time<75)) util=0.24;
			if (time>=75) util=0.27;
			
			float gf=((gravity-1.050)/0.2)+1;
			
			basicUtilization=util/gf;
			
			break;
		}
		case KPSRagersFormula:
		// Using Ragers's method
		{
			float gravityFactor=0;
			if (gravity>1.050) gravityFactor=(gravity-1.050)/0.2;
			basicUtilization=((18.11+(13.86*tanh((time-31.32)/18.27)))/(1+gravityFactor)/100);
			break;
		}
		case KPSGaretzFormula:
		// Using Garetz's method
		{
//			NSLog (@"Using Garetz's Formula");
			float util=0.0;
			if ((time>=11) && (time<16)) util=0.02;
			if ((time>=16) && (time<21)) util=0.05;
			if ((time>=21) && (time<26)) util=0.08;
			if ((time>=26) && (time<31)) util=0.11;
			if ((time>=31) && (time<36)) util=0.14;
			if ((time>=36) && (time<41)) util=0.16;
			if ((time>=41) && (time<46)) util=0.18;
			if ((time>=46) && (time<51)) util=0.19;
			if ((time>=51) && (time<61)) util=0.20;
			if ((time>=61) && (time<71)) util=0.21;
			if ((time>=71) && (time<81)) util=0.22;
			if (time>=81) util=0.23;
			
			// correction factors
			
			// There are other factors involved but BA doesn't use them
			
			float gf=((gravity-1.050)/0.2)+1;
			
			basicUtilization=util/gf;
			
			break;
		}
		default:
		{
			NSLog (@"Hop Formula Unsupported - returning zero");
			return 0;
			break;
		}
	}

Formula is an integer that describes the type of formula to be used. 'gravity' is the boil wort gravity in the form 1.0xx. Time is in minutes. basicUtilization is the percentage utilization as a fraction between 0 and 1.

[roger the dog]

From the actual BeerAlchemy code

Code: Select all

	switch (formula)
	{
		case KPSTinsethsFormula:
		// Using Tinseth's method
		{
			float bignessFactor=1.65 * pow(0.000125,gravity - 1);
			float boilTimeFactor=(1.0-exp(-0.04*time))/4.15;[/quote]

Surely that should be (0.00012[b]6[/b],gravity - 1) !

[steve_flack]

[Andy]