Home Calc Hub — Biltong & Solar Calculators

Spice Calculator

Proven, tested recipes using individual ingredients — scaled live to your batch weight. No premix required. All quantities calibrated from traditional South African methods.

🎛️ Inputs

Fresh Meat Weight

2 kg

Product Type

Include Worcestershire Sauce

Adds umami depth — listed in ingredients if on

📋 Recipe for Biltong

🌀 Droëwors — Meat Prep

Mince through a 13mm plate first. Add spice + vinegar and mix well. Then mince through a 4.5mm or 3mm plate. Fill casings and hang to dry at ≈30°C. Expect up to 50% weight loss when dry.

🔄 Mince Wiele — Special Steps

1. Season mince as per recipe above.
2. Stuff tightly into polony casings (65–75mm diameter).
3. Freeze the loaf solid (overnight minimum).
4. Remove the plastic casing before slicing.
5. A small meat band saw is essential for slicing the frozen loaf cleanly into 20–25mm rings. A knife will not cut through the frozen loaf. If you don't have a band saw, ask your butcher — if you buy your mince from him, he will often slice the loaf for you on his band saw.
6. Critical: Immediately wipe all cut faces (both flat surfaces of each ring) with brown vinegar — this prevents surface mould on the exposed mince.
7. ⚠️ Wiele cannot be hung. Lay rings flat on a wire rack in your biltong box — do not attempt to hang them.

Drying Time Estimator

Based on a 4-phase drying model derived from real biltong box sensor data. Enter your conditions for an estimate with ±20% accuracy.

🎛️ Drying Conditions

Meat Thickness (mm)

25 mm

Cut / Form Type

Ambient Temperature (°C)

22°C

Relative Humidity (%)

55%

Airflow / Fan Setup

Drying Environment

Target Doneness

Hours Already Elapsed (optional)

0 h

Estimated Drying Time

– days

–

📊 4-Phase Drying Model

Stabilising

Active Drying

Near Done

Done

💡 About this model: Phase durations are derived from humidity-delta sensor logging in a real biltong box. The key metric is the absolute humidity delta (inside − outside) — Active Drying is when this peaks; Near Done is when it falls below 60% of peak; Done is when rate of change approaches zero. Your actual result may vary ±20% based on meat fat content, curing, and airflow uniformity.

Batch Planner

Plan your batch economics, expected yield, and ready date. Weight-loss ratios are based on observed results across wet, medium, and dry doneness levels.

🎛️ Batch Details

Fresh Meat Weight (kg)

Price Paid per kg (R)

Target Doneness

Store Biltong Price (R/kg) — for comparison

Batch Start Date

Estimated Drying Days

← Use Drying Time tab to calculate this

💰 Batch Economics

📅 Timeline

Food Safety Checker

Answer these questions about your batch to get a safety assessment. Critical for first-time makers and anyone trying new formats like mince wiele.

❓ Your Batch Conditions

Product Type

Spice applied to all surfaces?

Including coarse salt from the dry spice mix

Vinegar applied to all surfaces?

Creates acidic surface barrier against mould

Cure / Marinate Time (hours)

Meat Thickness at Thickest Point (mm)

Drying Temperature (°C)

Average Humidity During Drying (%)

Cut faces wiped with vinegar? (Wiele only)

Prevents mould on flat sliced surfaces

Refrigerated during curing?

Recommended for ambient temps above 25°C

Safety Assessment

✅

Safe to proceed

📋 Safety Checklist

💡 White mould on biltong: Surface mould on whole muscle biltong is usually Penicillium — wipe off with vinegar-soaked cloth and continue drying. However, mould on mince wiele flat cut faces is more serious — discard if widespread. Always trust your nose: off-smell = discard.

Country / Region Currency Symbol Rate (per kWh)

Custom rate /kWh

Solar System Sizer

Enter your electricity bill and location — we calculate the exact system size, number of panels, and inverter you need. No installer bias, no lead capture. Just accurate numbers.

💡 Your Electricity

Input Method

Average Monthly Bill (R)

Province (sets peak sun hours)

Roof Orientation

🧭North
Best

🌅East
−15%

🌇West
−15%

🏠Multi-string
Custom

Panel Wattage

Goal

Recommended System Size

– kW

–

Panels Needed

–panels

–

Inverter Size

–kW

25% headroom above system

Daily Production

–kWh

avg good weather day

Monthly Production

–kWh

–

Your Daily Usage

–kWh

–

Peak Sun Hours

–hrs/day

for selected province

⚠️ Important Sizing Notes

Enter your details to see personalised notes.

🏠 Real-world reference: A 10kW system with two roof strings (7kW north-facing house roof + 5.5kW garage) in Pretoria produces approximately 45–50 kWh on a good summer day and 30–35 kWh in winter. System losses average 15–18% in practice.

Household Load Planner

Build your actual daily load from appliances. Enable/disable each item and adjust hours per day. Results feed directly into the System Sizer and Backup tabs.

🔌 Appliances

	Appliance	Watts	Hrs/day	kWh/day

Total Daily Usage

0.0 kWh

–

Peak Load (simultaneous)

–W

determines inverter minimum

Monthly kWh

–

× 30 days

Est. Monthly Bill

–

using selected rate

Biggest Load

–

highest single consumer

📊 Load Breakdown

💡 Use this tab's results as your kWh input in the System Sizer tab for a precise system size based on your actual appliances.

Savings & Return on Investment

See your payback period, 10-year savings, and how fast-rising Eskom tariffs make solar increasingly valuable every year. All calculations include realistic system degradation.

💰 System & Costs

Total Installed System Cost (R)

Typical 2026 SA pricing: R75k–R120k for 5kW without batteries · R105k–R200k with 10kWh battery

Current Monthly Bill (R)

% of Bill Offset by Solar

85%

Annual Eskom Tariff Increase (%)

12%

Historical SA average: 12–15% annually. Conservative = 10%, realistic = 12%

Panel Degradation per Year (%)

0.5%

Industry standard: 0.5%/year. Most panels warrantied at 80% output after 25 years.

Solar Tax Rebate –

🇿🇦 SA: 25% of cost, capped at R15,000 (SARS Section 6C). 🇬🇧 UK: No residential solar rebate currently. 🇦🇺 AU: STCs (Small-scale Technology Certificates) — typically A$2,000–A$5,000 off system cost. 🇩🇪 DE: 0% VAT on residential solar since 2023. Other countries: enter 0 if no rebate applies.

Payback Period

– yrs

–

Net Cost After Rebate

–

after SARS rebate

Year 1 Monthly Saving

–

on electricity bill

10-Year Total Saving

–

vs staying on grid

25-Year Total Saving

–

panel warranty lifetime

📊 Eskom vs Solar Cost per kWh

📅 Year-by-Year Savings

Year	Eskom Rate	Monthly Saving	Annual Saving	Cumulative

Load Shedding Backup Sizer

Not ready for full solar yet? Size a backup battery and inverter just for surviving load shedding. Select what you need to keep running and for how long.

🔌 What Must Stay On During Load Shedding?

Load Shedding Duration

Battery Type Preference

⚡ Usable capacity: Lithium batteries can use 80–90% of rated capacity. Gel/AGM should only use 50% to protect battery life. This calculator accounts for this automatically.

Battery Capacity Needed

– kWh

–

Total Load

–W

simultaneous draw

Minimum Inverter

–kVA

peak load + 25% headroom

Raw kWh Needed

–kWh

load × hours

Battery Rated Capacity

–kWh

–

🛒 What to Buy

Select appliances to see recommendations.

🔋 Real-world reference: A 10.2 kWh LiFePO4 battery (like SolaX/Deye/Revov) with a 5kW inverter running lights, WiFi, fridge, TV and decoder will last approximately 6–8 hours. Adding an air conditioner reduces this to 2–3 hours.