Mushroom BRF Cake Yield Calculator
Estimate fresh mushroom yield from BRF (brown rice flour) cakes by jar size and number of flushes.
Get fresh weight per jar across full fruiting cycle.
BRF Cake Yield (PF Tek)
PF Tek (the classic Psilocybe Fanaticus method) uses brown rice flour + vermiculite cakes in canning jars. Yield per cake depends on jar size, contamination luck, and temperature/humidity control.
Standard half-pint cake yield (PF Tek baseline):
| Flush # | Fresh Yield (g) |
|---|---|
| First flush (BFRT - Best First Flush) | 8-15 g per cake |
| Second flush | 5-10 g per cake |
| Third flush | 3-6 g per cake |
| Fourth flush (rarely worth dunking) | 1-3 g per cake |
| Total typical yield | 18-32 g per half-pint cake |
Jar size scaling:
| Jar Size | Substrate Volume | Typical Total Yield |
|---|---|---|
| Half-pint (8 oz) | ~125 ml | 18-32 g fresh |
| Pint (16 oz) | ~250 ml | 30-55 g fresh |
| Quart (32 oz) | ~500 ml | 50-95 g fresh |
| Half-gallon (64 oz) | ~1000 ml | 90-180 g fresh |
Conversion: fresh to dry weight: Dry weight ≈ Fresh weight × 0.10 (Mushrooms are 90% water; dried weight is roughly one-tenth of fresh.)
Fruiting condition multipliers:
- Optimal temp (74-78°F / 23-26°C): 1.0× yield
- Cool (65-73°F): 0.7× yield, longer fruiting time
- Warm (78-82°F): 0.85× yield, faster contamination risk
- Bad humidity (under 80% RH): 0.5× yield
- Excellent humidity (90-95%) with FAE: 1.2× yield
Strain genetics:
- Generic GT cubensis: baseline 1.0× yield
- Albino strains (PE, AA): 0.7-0.85× yield, slower
- Aggressive strains (B+, Golden Teacher): 1.0-1.1× yield
- Massive yielders (PESA, Penis Envy): 1.2-1.5× yield, slower colonization
Typical timeline:
- Inoculation to colonization: 14-28 days
- Birth (dunk + roll): day 28-35
- First flush: day 38-45 (after birth + 5-10 days fruiting)
- Second flush: day 50-60
- Third flush: day 65-75
- Total cycle: 70-90 days
Common mistakes that reduce yield:
- Not dunking enough between flushes (24+ hours in cold water)
- Insufficient FAE (Fresh Air Exchange) — leads to long stems, small caps
- Too low humidity (under 85%) — aborts and shrivels
- Light too low — makes pin development uneven
- Spore-print harvest — leaves spores fall everywhere, contam risk
For higher yields, growers move to bulk substrate (manure, BRF/coir, straw bags) which yields 5-15× as much per dollar of inputs but requires sterile technique and more space.